Commit-ID: 9a58eebe1ace609bedf8c5a65e70a097459f5696 Gitweb: http://git.kernel.org/tip/9a58eebe1ace609bedf8c5a65e70a097459f5696 Author: Toshi Kani <toshi.k...@hp.com> AuthorDate: Thu, 16 Jul 2015 17:23:15 -0600 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Wed, 22 Jul 2015 17:20:34 +0200
x86/mm: Remove region_is_ram() call from ioremap __ioremap_caller() calls region_is_ram() to walk through the iomem_resource table to check if a target range is in RAM, which was added to improve the lookup performance over page_is_ram() (commit 906e36c5c717 "x86: use optimized ioresource lookup in ioremap function"). page_is_ram() was no longer used when this change was added, though. __ioremap_caller() then calls walk_system_ram_range(), which had replaced page_is_ram() to improve the lookup performance (commit c81c8a1eeede "x86, ioremap: Speed up check for RAM pages"). Since both checks walk through the same iomem_resource table for the same purpose, there is no need to call both functions. Aside of that walk_system_ram_range() is the only useful check at the moment because region_is_ram() always returns -1 due to an implementation bug. That bug in region_is_ram() cannot be fixed without breaking existing ioremap callers, which rely on the subtle difference of walk_system_ram_range() versus non page aligned ranges. Once these offending callers are fixed we can use region_is_ram() and remove walk_system_ram_range(). [ tglx: Massaged changelog ] Signed-off-by: Toshi Kani <toshi.k...@hp.com> Reviewed-by: Dan Williams <dan.j.willi...@intel.com> Cc: Roland Dreier <rol...@purestorage.com> Cc: Mike Travis <tra...@sgi.com> Cc: Luis R. Rodriguez <mcg...@suse.com> Cc: H. Peter Anvin <h...@zytor.com> Cc: Ingo Molnar <mi...@redhat.com> Cc: Borislav Petkov <b...@alien8.de> Cc: linux...@kvack.org Link: http://lkml.kernel.org/r/1437088996-28511-3-git-send-email-toshi.k...@hp.com Signed-off-by: Thomas Gleixner <t...@linutronix.de> --- arch/x86/mm/ioremap.c | 24 ++++++------------------ 1 file changed, 6 insertions(+), 18 deletions(-) diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index fd3df0d..b9d4a33 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -92,7 +92,6 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr, pgprot_t prot; int retval; void __iomem *ret_addr; - int ram_region; /* Don't allow wraparound or zero size */ last_addr = phys_addr + size - 1; @@ -115,26 +114,15 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr, /* * Don't allow anybody to remap normal RAM that we're using.. */ - /* First check if whole region can be identified as RAM or not */ - ram_region = region_is_ram(phys_addr, size); - if (ram_region > 0) { - WARN_ONCE(1, "ioremap on RAM at 0x%lx - 0x%lx\n", - (unsigned long int)phys_addr, - (unsigned long int)last_addr); - return NULL; - } - - /* If could not be identified(-1), check page by page */ - if (ram_region < 0) { - pfn = phys_addr >> PAGE_SHIFT; - last_pfn = last_addr >> PAGE_SHIFT; - if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL, + pfn = phys_addr >> PAGE_SHIFT; + last_pfn = last_addr >> PAGE_SHIFT; + if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL, __ioremap_check_ram) == 1) { - WARN_ONCE(1, "ioremap on RAM at 0x%llx - 0x%llx\n", + WARN_ONCE(1, "ioremap on RAM at 0x%llx - 0x%llx\n", phys_addr, last_addr); - return NULL; - } + return NULL; } + /* * Mappings have to be page-aligned */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
