Re: [PATCH] mm: Create the new vm_fault_t type
On Tue, Nov 6, 2018 at 11:51 AM Mike Rapoport wrote: > > On Mon, Nov 05, 2018 at 07:23:55PM +0530, Souptick Joarder wrote: > > On Mon, Nov 5, 2018 at 2:43 PM Mike Rapoport wrote: > > > > > > On Mon, Nov 05, 2018 at 11:14:17AM +0530, Souptick Joarder wrote: > > > > Hi Matthew, > > > > > > > > On Sun, Nov 4, 2018 at 2:06 PM Mike Rapoport wrote: > > > > > > > > > > On Sat, Nov 03, 2018 at 05:02:36AM -0700, Matthew Wilcox wrote: > > > > > > On Sat, Nov 03, 2018 at 10:35:04AM +0530, Souptick Joarder wrote: > > > > > > > > +typedef __bitwise unsigned int vm_fault_t; > > > > > > > + > > > > > > > +/** > > > > > > > + * enum - VM_FAULT code > > > > > > > > > > > > Can you document an anonymous enum? I've never tried. Did you run > > > > > > this > > > > > > through 'make htmldocs'? > > > > > > > > > > You cannot document an anonymous enum. > > > > > > > > I assume, you are pointing to Document folder and I don't know if this > > > > enum need to be documented or not. > > > > > > The enum should be documented, even if it's documentation is (yet) not > > > linked anywhere in the Documentation/ > > > > > > > I didn't run 'make htmldocs' as there is no document related changes. > > > > > > You can verify that kernel-doc can parse your documentation by running > > > > > > scripts/kernel-doc -none -v > > > > I run "scripts/kernel-doc -none -v include/linux/mm_types.h" and it is > > showing > > below error and warning which is linked to enum in discussion. > > > > include/linux/mm_types.h:612: info: Scanning doc for typedef vm_fault_t > > include/linux/mm_types.h:623: info: Scanning doc for enum > > include/linux/mm_types.h:628: warning: contents before sections > > include/linux/mm_types.h:660: error: Cannot parse enum! > > 1 errors > > 1 warnings > > > > Shall I keep the documentation for enum or remove it from this patch ? > > The documentation should be there, you just need to add a name for the > enum. Then kernel-doc will be able to parse it. > > > > > > > > > > > > > + * This enum is used to track the VM_FAULT code return by page > > > > > > > + * fault handlers. > > > > > > > > I think that the enum description should also include the text from the > comment that described VM_FAULT_* defines: > > /* > * Different kinds of faults, as returned by handle_mm_fault(). > * Used to decide whether a process gets delivered SIGBUS or > * just gets major/minor fault counters bumped up. > */ > Ok, will add both in v2. Thanks.
Re: [PATCH] mm: Create the new vm_fault_t type
On Tue, Nov 6, 2018 at 11:51 AM Mike Rapoport wrote: > > On Mon, Nov 05, 2018 at 07:23:55PM +0530, Souptick Joarder wrote: > > On Mon, Nov 5, 2018 at 2:43 PM Mike Rapoport wrote: > > > > > > On Mon, Nov 05, 2018 at 11:14:17AM +0530, Souptick Joarder wrote: > > > > Hi Matthew, > > > > > > > > On Sun, Nov 4, 2018 at 2:06 PM Mike Rapoport wrote: > > > > > > > > > > On Sat, Nov 03, 2018 at 05:02:36AM -0700, Matthew Wilcox wrote: > > > > > > On Sat, Nov 03, 2018 at 10:35:04AM +0530, Souptick Joarder wrote: > > > > > > > > +typedef __bitwise unsigned int vm_fault_t; > > > > > > > + > > > > > > > +/** > > > > > > > + * enum - VM_FAULT code > > > > > > > > > > > > Can you document an anonymous enum? I've never tried. Did you run > > > > > > this > > > > > > through 'make htmldocs'? > > > > > > > > > > You cannot document an anonymous enum. > > > > > > > > I assume, you are pointing to Document folder and I don't know if this > > > > enum need to be documented or not. > > > > > > The enum should be documented, even if it's documentation is (yet) not > > > linked anywhere in the Documentation/ > > > > > > > I didn't run 'make htmldocs' as there is no document related changes. > > > > > > You can verify that kernel-doc can parse your documentation by running > > > > > > scripts/kernel-doc -none -v > > > > I run "scripts/kernel-doc -none -v include/linux/mm_types.h" and it is > > showing > > below error and warning which is linked to enum in discussion. > > > > include/linux/mm_types.h:612: info: Scanning doc for typedef vm_fault_t > > include/linux/mm_types.h:623: info: Scanning doc for enum > > include/linux/mm_types.h:628: warning: contents before sections > > include/linux/mm_types.h:660: error: Cannot parse enum! > > 1 errors > > 1 warnings > > > > Shall I keep the documentation for enum or remove it from this patch ? > > The documentation should be there, you just need to add a name for the > enum. Then kernel-doc will be able to parse it. > > > > > > > > > > > > > + * This enum is used to track the VM_FAULT code return by page > > > > > > > + * fault handlers. > > > > > > > > I think that the enum description should also include the text from the > comment that described VM_FAULT_* defines: > > /* > * Different kinds of faults, as returned by handle_mm_fault(). > * Used to decide whether a process gets delivered SIGBUS or > * just gets major/minor fault counters bumped up. > */ > Ok, will add both in v2. Thanks.
Re: [PATCH] mm: Create the new vm_fault_t type
On Mon, Nov 05, 2018 at 07:23:55PM +0530, Souptick Joarder wrote: > On Mon, Nov 5, 2018 at 2:43 PM Mike Rapoport wrote: > > > > On Mon, Nov 05, 2018 at 11:14:17AM +0530, Souptick Joarder wrote: > > > Hi Matthew, > > > > > > On Sun, Nov 4, 2018 at 2:06 PM Mike Rapoport wrote: > > > > > > > > On Sat, Nov 03, 2018 at 05:02:36AM -0700, Matthew Wilcox wrote: > > > > > On Sat, Nov 03, 2018 at 10:35:04AM +0530, Souptick Joarder wrote: > > > > > > +typedef __bitwise unsigned int vm_fault_t; > > > > > > + > > > > > > +/** > > > > > > + * enum - VM_FAULT code > > > > > > > > > > Can you document an anonymous enum? I've never tried. Did you run > > > > > this > > > > > through 'make htmldocs'? > > > > > > > > You cannot document an anonymous enum. > > > > > > I assume, you are pointing to Document folder and I don't know if this > > > enum need to be documented or not. > > > > The enum should be documented, even if it's documentation is (yet) not > > linked anywhere in the Documentation/ > > > > > I didn't run 'make htmldocs' as there is no document related changes. > > > > You can verify that kernel-doc can parse your documentation by running > > > > scripts/kernel-doc -none -v > > I run "scripts/kernel-doc -none -v include/linux/mm_types.h" and it is showing > below error and warning which is linked to enum in discussion. > > include/linux/mm_types.h:612: info: Scanning doc for typedef vm_fault_t > include/linux/mm_types.h:623: info: Scanning doc for enum > include/linux/mm_types.h:628: warning: contents before sections > include/linux/mm_types.h:660: error: Cannot parse enum! > 1 errors > 1 warnings > > Shall I keep the documentation for enum or remove it from this patch ? The documentation should be there, you just need to add a name for the enum. Then kernel-doc will be able to parse it. > > > > > > > > > > + * This enum is used to track the VM_FAULT code return by page > > > > > > + * fault handlers. > > > > > I think that the enum description should also include the text from the comment that described VM_FAULT_* defines: /* * Different kinds of faults, as returned by handle_mm_fault(). * Used to decide whether a process gets delivered SIGBUS or * just gets major/minor fault counters bumped up. */ -- Sincerely yours, Mike.
Re: [PATCH] mm: Create the new vm_fault_t type
On Mon, Nov 05, 2018 at 07:23:55PM +0530, Souptick Joarder wrote: > On Mon, Nov 5, 2018 at 2:43 PM Mike Rapoport wrote: > > > > On Mon, Nov 05, 2018 at 11:14:17AM +0530, Souptick Joarder wrote: > > > Hi Matthew, > > > > > > On Sun, Nov 4, 2018 at 2:06 PM Mike Rapoport wrote: > > > > > > > > On Sat, Nov 03, 2018 at 05:02:36AM -0700, Matthew Wilcox wrote: > > > > > On Sat, Nov 03, 2018 at 10:35:04AM +0530, Souptick Joarder wrote: > > > > > > +typedef __bitwise unsigned int vm_fault_t; > > > > > > + > > > > > > +/** > > > > > > + * enum - VM_FAULT code > > > > > > > > > > Can you document an anonymous enum? I've never tried. Did you run > > > > > this > > > > > through 'make htmldocs'? > > > > > > > > You cannot document an anonymous enum. > > > > > > I assume, you are pointing to Document folder and I don't know if this > > > enum need to be documented or not. > > > > The enum should be documented, even if it's documentation is (yet) not > > linked anywhere in the Documentation/ > > > > > I didn't run 'make htmldocs' as there is no document related changes. > > > > You can verify that kernel-doc can parse your documentation by running > > > > scripts/kernel-doc -none -v > > I run "scripts/kernel-doc -none -v include/linux/mm_types.h" and it is showing > below error and warning which is linked to enum in discussion. > > include/linux/mm_types.h:612: info: Scanning doc for typedef vm_fault_t > include/linux/mm_types.h:623: info: Scanning doc for enum > include/linux/mm_types.h:628: warning: contents before sections > include/linux/mm_types.h:660: error: Cannot parse enum! > 1 errors > 1 warnings > > Shall I keep the documentation for enum or remove it from this patch ? The documentation should be there, you just need to add a name for the enum. Then kernel-doc will be able to parse it. > > > > > > > > > > + * This enum is used to track the VM_FAULT code return by page > > > > > > + * fault handlers. > > > > > I think that the enum description should also include the text from the comment that described VM_FAULT_* defines: /* * Different kinds of faults, as returned by handle_mm_fault(). * Used to decide whether a process gets delivered SIGBUS or * just gets major/minor fault counters bumped up. */ -- Sincerely yours, Mike.
Re: [PATCH] mm: Create the new vm_fault_t type
On Mon, Nov 5, 2018 at 2:43 PM Mike Rapoport wrote: > > On Mon, Nov 05, 2018 at 11:14:17AM +0530, Souptick Joarder wrote: > > Hi Matthew, > > > > On Sun, Nov 4, 2018 at 2:06 PM Mike Rapoport wrote: > > > > > > On Sat, Nov 03, 2018 at 05:02:36AM -0700, Matthew Wilcox wrote: > > > > On Sat, Nov 03, 2018 at 10:35:04AM +0530, Souptick Joarder wrote: > > > > > Page fault handlers are supposed to return VM_FAULT codes, > > > > > but some drivers/file systems mistakenly return error > > > > > numbers. Now that all drivers/file systems have been converted > > > > > to use the vm_fault_t return type, change the type definition > > > > > to no longer be compatible with 'int'. By making it an unsigned > > > > > int, the function prototype becomes incompatible with a function > > > > > which returns int. Sparse will detect any attempts to return a > > > > > value which is not a VM_FAULT code. > > > > > > > > > > > > > -/* Encode hstate index for a hwpoisoned large page */ > > > > > -#define VM_FAULT_SET_HINDEX(x) ((x) << 12) > > > > > -#define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf) > > > > ... > > > > > +/* Encode hstate index for a hwpoisoned large page */ > > > > > +#define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16)) > > > > > +#define VM_FAULT_GET_HINDEX(x) (((x) >> 16) & 0xf) > > > > > > > > I think it's important to mention in the changelog that these values > > > > have been changed to avoid conflicts with other VM_FAULT codes. > > > > > > > > > +/** > > > > > + * typedef vm_fault_t - __bitwise unsigned int > > > > > + * > > > > > + * vm_fault_t is the new unsigned int type to return VM_FAULT > > > > > + * code by page fault handlers of drivers/file systems. Now if > > > > > + * any page fault handlers returns non VM_FAULT code instead > > > > > + * of VM_FAULT code, it will be a mismatch with function > > > > > + * prototype and sparse will detect it. > > > > > + */ > > > > > > > > The first line should be what the typedef *means*, not repeat the > > > > compiler's definition. The rest of the description should be > > > > information > > > > for someone coming to the type for the first time; what you've written > > > > here is changelog material. > > > > > > > > /** > > > > * typedef vm_fault_t - Return type for page fault handlers. > > > > * > > > > * Page fault handlers return a bitmask of %VM_FAULT values. > > > > */ > > > > > > > > > +typedef __bitwise unsigned int vm_fault_t; > > > > > + > > > > > +/** > > > > > + * enum - VM_FAULT code > > > > > > > > Can you document an anonymous enum? I've never tried. Did you run this > > > > through 'make htmldocs'? > > > > > > You cannot document an anonymous enum. > > > > > > I assume, you are pointing to Document folder and I don't know if this > > enum need to be documented or not. > > The enum should be documented, even if it's documentation is (yet) not > linked anywhere in the Documentation/ > > > I didn't run 'make htmldocs' as there is no document related changes. > > You can verify that kernel-doc can parse your documentation by running > > scripts/kernel-doc -none -v I run "scripts/kernel-doc -none -v include/linux/mm_types.h" and it is showing below error and warning which is linked to enum in discussion. include/linux/mm_types.h:612: info: Scanning doc for typedef vm_fault_t include/linux/mm_types.h:623: info: Scanning doc for enum include/linux/mm_types.h:628: warning: contents before sections include/linux/mm_types.h:660: error: Cannot parse enum! 1 errors 1 warnings Shall I keep the documentation for enum or remove it from this patch ? > > > > > > > > > + * This enum is used to track the VM_FAULT code return by page > > > > > + * fault handlers. > > > > > > > > * Page fault handlers return a bitmask of these values to tell the > > > > * core VM what happened when handling the fault. > > > > > > > > > > -- > > > Sincerely yours, > > > Mike. > > > > > > > -- > Sincerely yours, > Mike. >
Re: [PATCH] mm: Create the new vm_fault_t type
On Mon, Nov 5, 2018 at 2:43 PM Mike Rapoport wrote: > > On Mon, Nov 05, 2018 at 11:14:17AM +0530, Souptick Joarder wrote: > > Hi Matthew, > > > > On Sun, Nov 4, 2018 at 2:06 PM Mike Rapoport wrote: > > > > > > On Sat, Nov 03, 2018 at 05:02:36AM -0700, Matthew Wilcox wrote: > > > > On Sat, Nov 03, 2018 at 10:35:04AM +0530, Souptick Joarder wrote: > > > > > Page fault handlers are supposed to return VM_FAULT codes, > > > > > but some drivers/file systems mistakenly return error > > > > > numbers. Now that all drivers/file systems have been converted > > > > > to use the vm_fault_t return type, change the type definition > > > > > to no longer be compatible with 'int'. By making it an unsigned > > > > > int, the function prototype becomes incompatible with a function > > > > > which returns int. Sparse will detect any attempts to return a > > > > > value which is not a VM_FAULT code. > > > > > > > > > > > > > -/* Encode hstate index for a hwpoisoned large page */ > > > > > -#define VM_FAULT_SET_HINDEX(x) ((x) << 12) > > > > > -#define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf) > > > > ... > > > > > +/* Encode hstate index for a hwpoisoned large page */ > > > > > +#define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16)) > > > > > +#define VM_FAULT_GET_HINDEX(x) (((x) >> 16) & 0xf) > > > > > > > > I think it's important to mention in the changelog that these values > > > > have been changed to avoid conflicts with other VM_FAULT codes. > > > > > > > > > +/** > > > > > + * typedef vm_fault_t - __bitwise unsigned int > > > > > + * > > > > > + * vm_fault_t is the new unsigned int type to return VM_FAULT > > > > > + * code by page fault handlers of drivers/file systems. Now if > > > > > + * any page fault handlers returns non VM_FAULT code instead > > > > > + * of VM_FAULT code, it will be a mismatch with function > > > > > + * prototype and sparse will detect it. > > > > > + */ > > > > > > > > The first line should be what the typedef *means*, not repeat the > > > > compiler's definition. The rest of the description should be > > > > information > > > > for someone coming to the type for the first time; what you've written > > > > here is changelog material. > > > > > > > > /** > > > > * typedef vm_fault_t - Return type for page fault handlers. > > > > * > > > > * Page fault handlers return a bitmask of %VM_FAULT values. > > > > */ > > > > > > > > > +typedef __bitwise unsigned int vm_fault_t; > > > > > + > > > > > +/** > > > > > + * enum - VM_FAULT code > > > > > > > > Can you document an anonymous enum? I've never tried. Did you run this > > > > through 'make htmldocs'? > > > > > > You cannot document an anonymous enum. > > > > > > I assume, you are pointing to Document folder and I don't know if this > > enum need to be documented or not. > > The enum should be documented, even if it's documentation is (yet) not > linked anywhere in the Documentation/ > > > I didn't run 'make htmldocs' as there is no document related changes. > > You can verify that kernel-doc can parse your documentation by running > > scripts/kernel-doc -none -v I run "scripts/kernel-doc -none -v include/linux/mm_types.h" and it is showing below error and warning which is linked to enum in discussion. include/linux/mm_types.h:612: info: Scanning doc for typedef vm_fault_t include/linux/mm_types.h:623: info: Scanning doc for enum include/linux/mm_types.h:628: warning: contents before sections include/linux/mm_types.h:660: error: Cannot parse enum! 1 errors 1 warnings Shall I keep the documentation for enum or remove it from this patch ? > > > > > > > > > + * This enum is used to track the VM_FAULT code return by page > > > > > + * fault handlers. > > > > > > > > * Page fault handlers return a bitmask of these values to tell the > > > > * core VM what happened when handling the fault. > > > > > > > > > > -- > > > Sincerely yours, > > > Mike. > > > > > > > -- > Sincerely yours, > Mike. >
Re: [PATCH] mm: Create the new vm_fault_t type
On Mon, Nov 05, 2018 at 11:14:17AM +0530, Souptick Joarder wrote: > Hi Matthew, > > On Sun, Nov 4, 2018 at 2:06 PM Mike Rapoport wrote: > > > > On Sat, Nov 03, 2018 at 05:02:36AM -0700, Matthew Wilcox wrote: > > > On Sat, Nov 03, 2018 at 10:35:04AM +0530, Souptick Joarder wrote: > > > > Page fault handlers are supposed to return VM_FAULT codes, > > > > but some drivers/file systems mistakenly return error > > > > numbers. Now that all drivers/file systems have been converted > > > > to use the vm_fault_t return type, change the type definition > > > > to no longer be compatible with 'int'. By making it an unsigned > > > > int, the function prototype becomes incompatible with a function > > > > which returns int. Sparse will detect any attempts to return a > > > > value which is not a VM_FAULT code. > > > > > > > > > > -/* Encode hstate index for a hwpoisoned large page */ > > > > -#define VM_FAULT_SET_HINDEX(x) ((x) << 12) > > > > -#define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf) > > > ... > > > > +/* Encode hstate index for a hwpoisoned large page */ > > > > +#define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16)) > > > > +#define VM_FAULT_GET_HINDEX(x) (((x) >> 16) & 0xf) > > > > > > I think it's important to mention in the changelog that these values > > > have been changed to avoid conflicts with other VM_FAULT codes. > > > > > > > +/** > > > > + * typedef vm_fault_t - __bitwise unsigned int > > > > + * > > > > + * vm_fault_t is the new unsigned int type to return VM_FAULT > > > > + * code by page fault handlers of drivers/file systems. Now if > > > > + * any page fault handlers returns non VM_FAULT code instead > > > > + * of VM_FAULT code, it will be a mismatch with function > > > > + * prototype and sparse will detect it. > > > > + */ > > > > > > The first line should be what the typedef *means*, not repeat the > > > compiler's definition. The rest of the description should be information > > > for someone coming to the type for the first time; what you've written > > > here is changelog material. > > > > > > /** > > > * typedef vm_fault_t - Return type for page fault handlers. > > > * > > > * Page fault handlers return a bitmask of %VM_FAULT values. > > > */ > > > > > > > +typedef __bitwise unsigned int vm_fault_t; > > > > + > > > > +/** > > > > + * enum - VM_FAULT code > > > > > > Can you document an anonymous enum? I've never tried. Did you run this > > > through 'make htmldocs'? > > > > You cannot document an anonymous enum. > > > I assume, you are pointing to Document folder and I don't know if this > enum need to be documented or not. The enum should be documented, even if it's documentation is (yet) not linked anywhere in the Documentation/ > I didn't run 'make htmldocs' as there is no document related changes. You can verify that kernel-doc can parse your documentation by running scripts/kernel-doc -none -v > > > > > > + * This enum is used to track the VM_FAULT code return by page > > > > + * fault handlers. > > > > > > * Page fault handlers return a bitmask of these values to tell the > > > * core VM what happened when handling the fault. > > > > > > > -- > > Sincerely yours, > > Mike. > > > -- Sincerely yours, Mike.
Re: [PATCH] mm: Create the new vm_fault_t type
On Mon, Nov 05, 2018 at 11:14:17AM +0530, Souptick Joarder wrote: > Hi Matthew, > > On Sun, Nov 4, 2018 at 2:06 PM Mike Rapoport wrote: > > > > On Sat, Nov 03, 2018 at 05:02:36AM -0700, Matthew Wilcox wrote: > > > On Sat, Nov 03, 2018 at 10:35:04AM +0530, Souptick Joarder wrote: > > > > Page fault handlers are supposed to return VM_FAULT codes, > > > > but some drivers/file systems mistakenly return error > > > > numbers. Now that all drivers/file systems have been converted > > > > to use the vm_fault_t return type, change the type definition > > > > to no longer be compatible with 'int'. By making it an unsigned > > > > int, the function prototype becomes incompatible with a function > > > > which returns int. Sparse will detect any attempts to return a > > > > value which is not a VM_FAULT code. > > > > > > > > > > -/* Encode hstate index for a hwpoisoned large page */ > > > > -#define VM_FAULT_SET_HINDEX(x) ((x) << 12) > > > > -#define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf) > > > ... > > > > +/* Encode hstate index for a hwpoisoned large page */ > > > > +#define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16)) > > > > +#define VM_FAULT_GET_HINDEX(x) (((x) >> 16) & 0xf) > > > > > > I think it's important to mention in the changelog that these values > > > have been changed to avoid conflicts with other VM_FAULT codes. > > > > > > > +/** > > > > + * typedef vm_fault_t - __bitwise unsigned int > > > > + * > > > > + * vm_fault_t is the new unsigned int type to return VM_FAULT > > > > + * code by page fault handlers of drivers/file systems. Now if > > > > + * any page fault handlers returns non VM_FAULT code instead > > > > + * of VM_FAULT code, it will be a mismatch with function > > > > + * prototype and sparse will detect it. > > > > + */ > > > > > > The first line should be what the typedef *means*, not repeat the > > > compiler's definition. The rest of the description should be information > > > for someone coming to the type for the first time; what you've written > > > here is changelog material. > > > > > > /** > > > * typedef vm_fault_t - Return type for page fault handlers. > > > * > > > * Page fault handlers return a bitmask of %VM_FAULT values. > > > */ > > > > > > > +typedef __bitwise unsigned int vm_fault_t; > > > > + > > > > +/** > > > > + * enum - VM_FAULT code > > > > > > Can you document an anonymous enum? I've never tried. Did you run this > > > through 'make htmldocs'? > > > > You cannot document an anonymous enum. > > > I assume, you are pointing to Document folder and I don't know if this > enum need to be documented or not. The enum should be documented, even if it's documentation is (yet) not linked anywhere in the Documentation/ > I didn't run 'make htmldocs' as there is no document related changes. You can verify that kernel-doc can parse your documentation by running scripts/kernel-doc -none -v > > > > > > + * This enum is used to track the VM_FAULT code return by page > > > > + * fault handlers. > > > > > > * Page fault handlers return a bitmask of these values to tell the > > > * core VM what happened when handling the fault. > > > > > > > -- > > Sincerely yours, > > Mike. > > > -- Sincerely yours, Mike.
Re: [PATCH] mm: Create the new vm_fault_t type
Hi Matthew, On Sun, Nov 4, 2018 at 2:06 PM Mike Rapoport wrote: > > On Sat, Nov 03, 2018 at 05:02:36AM -0700, Matthew Wilcox wrote: > > On Sat, Nov 03, 2018 at 10:35:04AM +0530, Souptick Joarder wrote: > > > Page fault handlers are supposed to return VM_FAULT codes, > > > but some drivers/file systems mistakenly return error > > > numbers. Now that all drivers/file systems have been converted > > > to use the vm_fault_t return type, change the type definition > > > to no longer be compatible with 'int'. By making it an unsigned > > > int, the function prototype becomes incompatible with a function > > > which returns int. Sparse will detect any attempts to return a > > > value which is not a VM_FAULT code. > > > > > > > -/* Encode hstate index for a hwpoisoned large page */ > > > -#define VM_FAULT_SET_HINDEX(x) ((x) << 12) > > > -#define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf) > > ... > > > +/* Encode hstate index for a hwpoisoned large page */ > > > +#define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16)) > > > +#define VM_FAULT_GET_HINDEX(x) (((x) >> 16) & 0xf) > > > > I think it's important to mention in the changelog that these values > > have been changed to avoid conflicts with other VM_FAULT codes. > > > > > +/** > > > + * typedef vm_fault_t - __bitwise unsigned int > > > + * > > > + * vm_fault_t is the new unsigned int type to return VM_FAULT > > > + * code by page fault handlers of drivers/file systems. Now if > > > + * any page fault handlers returns non VM_FAULT code instead > > > + * of VM_FAULT code, it will be a mismatch with function > > > + * prototype and sparse will detect it. > > > + */ > > > > The first line should be what the typedef *means*, not repeat the > > compiler's definition. The rest of the description should be information > > for someone coming to the type for the first time; what you've written > > here is changelog material. > > > > /** > > * typedef vm_fault_t - Return type for page fault handlers. > > * > > * Page fault handlers return a bitmask of %VM_FAULT values. > > */ > > > > > +typedef __bitwise unsigned int vm_fault_t; > > > + > > > +/** > > > + * enum - VM_FAULT code > > > > Can you document an anonymous enum? I've never tried. Did you run this > > through 'make htmldocs'? > > You cannot document an anonymous enum. I assume, you are pointing to Document folder and I don't know if this enum need to be documented or not. I didn't run 'make htmldocs' as there is no document related changes. > > > > + * This enum is used to track the VM_FAULT code return by page > > > + * fault handlers. > > > > * Page fault handlers return a bitmask of these values to tell the > > * core VM what happened when handling the fault. > > > > -- > Sincerely yours, > Mike. >
Re: [PATCH] mm: Create the new vm_fault_t type
Hi Matthew, On Sun, Nov 4, 2018 at 2:06 PM Mike Rapoport wrote: > > On Sat, Nov 03, 2018 at 05:02:36AM -0700, Matthew Wilcox wrote: > > On Sat, Nov 03, 2018 at 10:35:04AM +0530, Souptick Joarder wrote: > > > Page fault handlers are supposed to return VM_FAULT codes, > > > but some drivers/file systems mistakenly return error > > > numbers. Now that all drivers/file systems have been converted > > > to use the vm_fault_t return type, change the type definition > > > to no longer be compatible with 'int'. By making it an unsigned > > > int, the function prototype becomes incompatible with a function > > > which returns int. Sparse will detect any attempts to return a > > > value which is not a VM_FAULT code. > > > > > > > -/* Encode hstate index for a hwpoisoned large page */ > > > -#define VM_FAULT_SET_HINDEX(x) ((x) << 12) > > > -#define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf) > > ... > > > +/* Encode hstate index for a hwpoisoned large page */ > > > +#define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16)) > > > +#define VM_FAULT_GET_HINDEX(x) (((x) >> 16) & 0xf) > > > > I think it's important to mention in the changelog that these values > > have been changed to avoid conflicts with other VM_FAULT codes. > > > > > +/** > > > + * typedef vm_fault_t - __bitwise unsigned int > > > + * > > > + * vm_fault_t is the new unsigned int type to return VM_FAULT > > > + * code by page fault handlers of drivers/file systems. Now if > > > + * any page fault handlers returns non VM_FAULT code instead > > > + * of VM_FAULT code, it will be a mismatch with function > > > + * prototype and sparse will detect it. > > > + */ > > > > The first line should be what the typedef *means*, not repeat the > > compiler's definition. The rest of the description should be information > > for someone coming to the type for the first time; what you've written > > here is changelog material. > > > > /** > > * typedef vm_fault_t - Return type for page fault handlers. > > * > > * Page fault handlers return a bitmask of %VM_FAULT values. > > */ > > > > > +typedef __bitwise unsigned int vm_fault_t; > > > + > > > +/** > > > + * enum - VM_FAULT code > > > > Can you document an anonymous enum? I've never tried. Did you run this > > through 'make htmldocs'? > > You cannot document an anonymous enum. I assume, you are pointing to Document folder and I don't know if this enum need to be documented or not. I didn't run 'make htmldocs' as there is no document related changes. > > > > + * This enum is used to track the VM_FAULT code return by page > > > + * fault handlers. > > > > * Page fault handlers return a bitmask of these values to tell the > > * core VM what happened when handling the fault. > > > > -- > Sincerely yours, > Mike. >
Re: [PATCH] mm: Create the new vm_fault_t type
On Sat, Nov 03, 2018 at 05:02:36AM -0700, Matthew Wilcox wrote: > On Sat, Nov 03, 2018 at 10:35:04AM +0530, Souptick Joarder wrote: > > Page fault handlers are supposed to return VM_FAULT codes, > > but some drivers/file systems mistakenly return error > > numbers. Now that all drivers/file systems have been converted > > to use the vm_fault_t return type, change the type definition > > to no longer be compatible with 'int'. By making it an unsigned > > int, the function prototype becomes incompatible with a function > > which returns int. Sparse will detect any attempts to return a > > value which is not a VM_FAULT code. > > > > -/* Encode hstate index for a hwpoisoned large page */ > > -#define VM_FAULT_SET_HINDEX(x) ((x) << 12) > > -#define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf) > ... > > +/* Encode hstate index for a hwpoisoned large page */ > > +#define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16)) > > +#define VM_FAULT_GET_HINDEX(x) (((x) >> 16) & 0xf) > > I think it's important to mention in the changelog that these values > have been changed to avoid conflicts with other VM_FAULT codes. > > > +/** > > + * typedef vm_fault_t - __bitwise unsigned int > > + * > > + * vm_fault_t is the new unsigned int type to return VM_FAULT > > + * code by page fault handlers of drivers/file systems. Now if > > + * any page fault handlers returns non VM_FAULT code instead > > + * of VM_FAULT code, it will be a mismatch with function > > + * prototype and sparse will detect it. > > + */ > > The first line should be what the typedef *means*, not repeat the > compiler's definition. The rest of the description should be information > for someone coming to the type for the first time; what you've written > here is changelog material. > > /** > * typedef vm_fault_t - Return type for page fault handlers. > * > * Page fault handlers return a bitmask of %VM_FAULT values. > */ > > > +typedef __bitwise unsigned int vm_fault_t; > > + > > +/** > > + * enum - VM_FAULT code > > Can you document an anonymous enum? I've never tried. Did you run this > through 'make htmldocs'? You cannot document an anonymous enum. > > + * This enum is used to track the VM_FAULT code return by page > > + * fault handlers. > > * Page fault handlers return a bitmask of these values to tell the > * core VM what happened when handling the fault. > -- Sincerely yours, Mike.
Re: [PATCH] mm: Create the new vm_fault_t type
On Sat, Nov 03, 2018 at 05:02:36AM -0700, Matthew Wilcox wrote: > On Sat, Nov 03, 2018 at 10:35:04AM +0530, Souptick Joarder wrote: > > Page fault handlers are supposed to return VM_FAULT codes, > > but some drivers/file systems mistakenly return error > > numbers. Now that all drivers/file systems have been converted > > to use the vm_fault_t return type, change the type definition > > to no longer be compatible with 'int'. By making it an unsigned > > int, the function prototype becomes incompatible with a function > > which returns int. Sparse will detect any attempts to return a > > value which is not a VM_FAULT code. > > > > -/* Encode hstate index for a hwpoisoned large page */ > > -#define VM_FAULT_SET_HINDEX(x) ((x) << 12) > > -#define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf) > ... > > +/* Encode hstate index for a hwpoisoned large page */ > > +#define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16)) > > +#define VM_FAULT_GET_HINDEX(x) (((x) >> 16) & 0xf) > > I think it's important to mention in the changelog that these values > have been changed to avoid conflicts with other VM_FAULT codes. > > > +/** > > + * typedef vm_fault_t - __bitwise unsigned int > > + * > > + * vm_fault_t is the new unsigned int type to return VM_FAULT > > + * code by page fault handlers of drivers/file systems. Now if > > + * any page fault handlers returns non VM_FAULT code instead > > + * of VM_FAULT code, it will be a mismatch with function > > + * prototype and sparse will detect it. > > + */ > > The first line should be what the typedef *means*, not repeat the > compiler's definition. The rest of the description should be information > for someone coming to the type for the first time; what you've written > here is changelog material. > > /** > * typedef vm_fault_t - Return type for page fault handlers. > * > * Page fault handlers return a bitmask of %VM_FAULT values. > */ > > > +typedef __bitwise unsigned int vm_fault_t; > > + > > +/** > > + * enum - VM_FAULT code > > Can you document an anonymous enum? I've never tried. Did you run this > through 'make htmldocs'? You cannot document an anonymous enum. > > + * This enum is used to track the VM_FAULT code return by page > > + * fault handlers. > > * Page fault handlers return a bitmask of these values to tell the > * core VM what happened when handling the fault. > -- Sincerely yours, Mike.
Re: [PATCH] mm: Create the new vm_fault_t type
On Sat, Nov 03, 2018 at 10:35:04AM +0530, Souptick Joarder wrote: > Page fault handlers are supposed to return VM_FAULT codes, > but some drivers/file systems mistakenly return error > numbers. Now that all drivers/file systems have been converted > to use the vm_fault_t return type, change the type definition > to no longer be compatible with 'int'. By making it an unsigned > int, the function prototype becomes incompatible with a function > which returns int. Sparse will detect any attempts to return a > value which is not a VM_FAULT code. > -/* Encode hstate index for a hwpoisoned large page */ > -#define VM_FAULT_SET_HINDEX(x) ((x) << 12) > -#define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf) ... > +/* Encode hstate index for a hwpoisoned large page */ > +#define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16)) > +#define VM_FAULT_GET_HINDEX(x) (((x) >> 16) & 0xf) I think it's important to mention in the changelog that these values have been changed to avoid conflicts with other VM_FAULT codes. > +/** > + * typedef vm_fault_t - __bitwise unsigned int > + * > + * vm_fault_t is the new unsigned int type to return VM_FAULT > + * code by page fault handlers of drivers/file systems. Now if > + * any page fault handlers returns non VM_FAULT code instead > + * of VM_FAULT code, it will be a mismatch with function > + * prototype and sparse will detect it. > + */ The first line should be what the typedef *means*, not repeat the compiler's definition. The rest of the description should be information for someone coming to the type for the first time; what you've written here is changelog material. /** * typedef vm_fault_t - Return type for page fault handlers. * * Page fault handlers return a bitmask of %VM_FAULT values. */ > +typedef __bitwise unsigned int vm_fault_t; > + > +/** > + * enum - VM_FAULT code Can you document an anonymous enum? I've never tried. Did you run this through 'make htmldocs'? > + * This enum is used to track the VM_FAULT code return by page > + * fault handlers. * Page fault handlers return a bitmask of these values to tell the * core VM what happened when handling the fault.
Re: [PATCH] mm: Create the new vm_fault_t type
On Sat, Nov 03, 2018 at 10:35:04AM +0530, Souptick Joarder wrote: > Page fault handlers are supposed to return VM_FAULT codes, > but some drivers/file systems mistakenly return error > numbers. Now that all drivers/file systems have been converted > to use the vm_fault_t return type, change the type definition > to no longer be compatible with 'int'. By making it an unsigned > int, the function prototype becomes incompatible with a function > which returns int. Sparse will detect any attempts to return a > value which is not a VM_FAULT code. > -/* Encode hstate index for a hwpoisoned large page */ > -#define VM_FAULT_SET_HINDEX(x) ((x) << 12) > -#define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf) ... > +/* Encode hstate index for a hwpoisoned large page */ > +#define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16)) > +#define VM_FAULT_GET_HINDEX(x) (((x) >> 16) & 0xf) I think it's important to mention in the changelog that these values have been changed to avoid conflicts with other VM_FAULT codes. > +/** > + * typedef vm_fault_t - __bitwise unsigned int > + * > + * vm_fault_t is the new unsigned int type to return VM_FAULT > + * code by page fault handlers of drivers/file systems. Now if > + * any page fault handlers returns non VM_FAULT code instead > + * of VM_FAULT code, it will be a mismatch with function > + * prototype and sparse will detect it. > + */ The first line should be what the typedef *means*, not repeat the compiler's definition. The rest of the description should be information for someone coming to the type for the first time; what you've written here is changelog material. /** * typedef vm_fault_t - Return type for page fault handlers. * * Page fault handlers return a bitmask of %VM_FAULT values. */ > +typedef __bitwise unsigned int vm_fault_t; > + > +/** > + * enum - VM_FAULT code Can you document an anonymous enum? I've never tried. Did you run this through 'make htmldocs'? > + * This enum is used to track the VM_FAULT code return by page > + * fault handlers. * Page fault handlers return a bitmask of these values to tell the * core VM what happened when handling the fault.
Re: [PATCH] mm: Create the new vm_fault_t type
On Sat, Nov 3, 2018 at 10:31 AM Souptick Joarder wrote:
>
> Page fault handlers are supposed to return VM_FAULT codes,
> but some drivers/file systems mistakenly return error
> numbers. Now that all drivers/file systems have been converted
> to use the vm_fault_t return type, change the type definition
> to no longer be compatible with 'int'. By making it an unsigned
> int, the function prototype becomes incompatible with a function
> which returns int. Sparse will detect any attempts to return a
> value which is not a VM_FAULT code.
>
> Signed-off-by: Souptick Joarder
> ---
> include/linux/mm.h | 46 -
> include/linux/mm_types.h | 75
> +++-
> 2 files changed, 74 insertions(+), 47 deletions(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index fcf9cc9..511a3ce 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1267,52 +1267,6 @@ static inline void clear_page_pfmemalloc(struct page
> *page)
> }
>
> /*
> - * Different kinds of faults, as returned by handle_mm_fault().
> - * Used to decide whether a process gets delivered SIGBUS or
> - * just gets major/minor fault counters bumped up.
> - */
> -
> -#define VM_FAULT_OOM 0x0001
> -#define VM_FAULT_SIGBUS0x0002
> -#define VM_FAULT_MAJOR 0x0004
> -#define VM_FAULT_WRITE 0x0008 /* Special case for get_user_pages */
> -#define VM_FAULT_HWPOISON 0x0010 /* Hit poisoned small page */
> -#define VM_FAULT_HWPOISON_LARGE 0x0020 /* Hit poisoned large page. Index
> encoded in upper bits */
> -#define VM_FAULT_SIGSEGV 0x0040
> -
> -#define VM_FAULT_NOPAGE0x0100 /* ->fault installed the pte, not
> return page */
> -#define VM_FAULT_LOCKED0x0200 /* ->fault locked the returned page */
> -#define VM_FAULT_RETRY 0x0400 /* ->fault blocked, must retry */
> -#define VM_FAULT_FALLBACK 0x0800 /* huge page fault failed, fall back
> to small */
> -#define VM_FAULT_DONE_COW 0x1000 /* ->fault has fully handled COW */
> -#define VM_FAULT_NEEDDSYNC 0x2000 /* ->fault did not modify page tables
> -* and needs fsync() to complete (for
> -* synchronous page faults in DAX) */
> -
> -#define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV | \
> -VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE | \
> -VM_FAULT_FALLBACK)
> -
> -#define VM_FAULT_RESULT_TRACE \
> - { VM_FAULT_OOM, "OOM" }, \
> - { VM_FAULT_SIGBUS, "SIGBUS" }, \
> - { VM_FAULT_MAJOR, "MAJOR" }, \
> - { VM_FAULT_WRITE, "WRITE" }, \
> - { VM_FAULT_HWPOISON,"HWPOISON" }, \
> - { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \
> - { VM_FAULT_SIGSEGV, "SIGSEGV" }, \
> - { VM_FAULT_NOPAGE, "NOPAGE" }, \
> - { VM_FAULT_LOCKED, "LOCKED" }, \
> - { VM_FAULT_RETRY, "RETRY" }, \
> - { VM_FAULT_FALLBACK,"FALLBACK" }, \
> - { VM_FAULT_DONE_COW,"DONE_COW" }, \
> - { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" }
> -
> -/* Encode hstate index for a hwpoisoned large page */
> -#define VM_FAULT_SET_HINDEX(x) ((x) << 12)
> -#define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf)
> -
> -/*
> * Can be called by the pagefault handler when it gets a VM_FAULT_OOM.
> */
> extern void pagefault_out_of_memory(void);
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index 5ed8f62..48c2108 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -22,7 +22,6 @@
> #endif
> #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))
>
> -typedef int vm_fault_t;
>
> struct address_space;
> struct mem_cgroup;
> @@ -609,6 +608,80 @@ static inline bool mm_tlb_flush_nested(struct mm_struct
> *mm)
>
> struct vm_fault;
>
> +/**
> + * typedef vm_fault_t - __bitwise unsigned int
> + *
> + * vm_fault_t is the new unsigned int type to return VM_FAULT
> + * code by page fault handlers of drivers/file systems. Now if
> + * any page fault handlers returns non VM_FAULT code instead
> + * of VM_FAULT code, it will be a mismatch with function
> + * prototype and sparse will detect it.
> + */
> +typedef __bitwise unsigned int vm_fault_t;
> +
> +/**
> + * enum - VM_FAULT code
> + *
> + * This enum is used to track the VM_FAULT code return by page
> + * fault handlers.
> + *
> + * @VM_FAULT_OOM: Out Of Memory
> + * @VM_FAULT_SIGBUS: Bad access
> + * @VM_FAULT_MAJOR:Page read from storage
> + * @VM_FAULT_WRITE:Special case for get_user_pages
> + * @VM_FAULT_HWPOISON: Hit poisoned small page
> + * @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded
> + * in upper bits
> + * @VM_FAULT_SIGSEGV:
Re: [PATCH] mm: Create the new vm_fault_t type
On Sat, Nov 3, 2018 at 10:31 AM Souptick Joarder wrote:
>
> Page fault handlers are supposed to return VM_FAULT codes,
> but some drivers/file systems mistakenly return error
> numbers. Now that all drivers/file systems have been converted
> to use the vm_fault_t return type, change the type definition
> to no longer be compatible with 'int'. By making it an unsigned
> int, the function prototype becomes incompatible with a function
> which returns int. Sparse will detect any attempts to return a
> value which is not a VM_FAULT code.
>
> Signed-off-by: Souptick Joarder
> ---
> include/linux/mm.h | 46 -
> include/linux/mm_types.h | 75
> +++-
> 2 files changed, 74 insertions(+), 47 deletions(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index fcf9cc9..511a3ce 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1267,52 +1267,6 @@ static inline void clear_page_pfmemalloc(struct page
> *page)
> }
>
> /*
> - * Different kinds of faults, as returned by handle_mm_fault().
> - * Used to decide whether a process gets delivered SIGBUS or
> - * just gets major/minor fault counters bumped up.
> - */
> -
> -#define VM_FAULT_OOM 0x0001
> -#define VM_FAULT_SIGBUS0x0002
> -#define VM_FAULT_MAJOR 0x0004
> -#define VM_FAULT_WRITE 0x0008 /* Special case for get_user_pages */
> -#define VM_FAULT_HWPOISON 0x0010 /* Hit poisoned small page */
> -#define VM_FAULT_HWPOISON_LARGE 0x0020 /* Hit poisoned large page. Index
> encoded in upper bits */
> -#define VM_FAULT_SIGSEGV 0x0040
> -
> -#define VM_FAULT_NOPAGE0x0100 /* ->fault installed the pte, not
> return page */
> -#define VM_FAULT_LOCKED0x0200 /* ->fault locked the returned page */
> -#define VM_FAULT_RETRY 0x0400 /* ->fault blocked, must retry */
> -#define VM_FAULT_FALLBACK 0x0800 /* huge page fault failed, fall back
> to small */
> -#define VM_FAULT_DONE_COW 0x1000 /* ->fault has fully handled COW */
> -#define VM_FAULT_NEEDDSYNC 0x2000 /* ->fault did not modify page tables
> -* and needs fsync() to complete (for
> -* synchronous page faults in DAX) */
> -
> -#define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV | \
> -VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE | \
> -VM_FAULT_FALLBACK)
> -
> -#define VM_FAULT_RESULT_TRACE \
> - { VM_FAULT_OOM, "OOM" }, \
> - { VM_FAULT_SIGBUS, "SIGBUS" }, \
> - { VM_FAULT_MAJOR, "MAJOR" }, \
> - { VM_FAULT_WRITE, "WRITE" }, \
> - { VM_FAULT_HWPOISON,"HWPOISON" }, \
> - { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \
> - { VM_FAULT_SIGSEGV, "SIGSEGV" }, \
> - { VM_FAULT_NOPAGE, "NOPAGE" }, \
> - { VM_FAULT_LOCKED, "LOCKED" }, \
> - { VM_FAULT_RETRY, "RETRY" }, \
> - { VM_FAULT_FALLBACK,"FALLBACK" }, \
> - { VM_FAULT_DONE_COW,"DONE_COW" }, \
> - { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" }
> -
> -/* Encode hstate index for a hwpoisoned large page */
> -#define VM_FAULT_SET_HINDEX(x) ((x) << 12)
> -#define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf)
> -
> -/*
> * Can be called by the pagefault handler when it gets a VM_FAULT_OOM.
> */
> extern void pagefault_out_of_memory(void);
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index 5ed8f62..48c2108 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -22,7 +22,6 @@
> #endif
> #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))
>
> -typedef int vm_fault_t;
>
> struct address_space;
> struct mem_cgroup;
> @@ -609,6 +608,80 @@ static inline bool mm_tlb_flush_nested(struct mm_struct
> *mm)
>
> struct vm_fault;
>
> +/**
> + * typedef vm_fault_t - __bitwise unsigned int
> + *
> + * vm_fault_t is the new unsigned int type to return VM_FAULT
> + * code by page fault handlers of drivers/file systems. Now if
> + * any page fault handlers returns non VM_FAULT code instead
> + * of VM_FAULT code, it will be a mismatch with function
> + * prototype and sparse will detect it.
> + */
> +typedef __bitwise unsigned int vm_fault_t;
> +
> +/**
> + * enum - VM_FAULT code
> + *
> + * This enum is used to track the VM_FAULT code return by page
> + * fault handlers.
> + *
> + * @VM_FAULT_OOM: Out Of Memory
> + * @VM_FAULT_SIGBUS: Bad access
> + * @VM_FAULT_MAJOR:Page read from storage
> + * @VM_FAULT_WRITE:Special case for get_user_pages
> + * @VM_FAULT_HWPOISON: Hit poisoned small page
> + * @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded
> + * in upper bits
> + * @VM_FAULT_SIGSEGV:
