Re: [PATCH 12/30] blk_end_request: changing ub (take 4)
On Fri, 14 Dec 2007 12:04:54 -0500 (EST), Kiyoshi Ueda <[EMAIL PROTECTED]> wrote: > I have investigated all code paths which call ub_end_rq() in ub.c, > and confirmed that ub_end_rq() is always called with the queue lock > held. (sc->lock is registered as a queue lock.) Thanks for reminding me about blk_init_queue, I forgot. Sorry for the confusion. Greetings, -- Pete -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 12/30] blk_end_request: changing ub (take 4)
Hi Pete, On Thu, 13 Dec 2007 13:59:16 -0800, Pete Zaitcev <[EMAIL PROTECTED]> wrote: > > > > - end_that_request_first(rq, uptodate, rq->hard_nr_sectors); > > > > - end_that_request_last(rq, uptodate); > > > > + if (__blk_end_request(rq, error, blk_rq_bytes(rq))) > > > > + BUG(); > > > > > > My understanding was, blk_end_request() is the same thing, only > > > takes the queue lock. But then, should I refactor ub so that it > > > calls __blk_end_request if request function ends with an error > > > and blk_end_request if the end-of-IO even is processed? > > > > I'm using __blk_end_request() here and I think it's sufficient, because: > > o end_that_request_last() must be called with the queue lock held > > o ub_end_rq() calls end_that_request_last() without taking > > the queue lock in itself. > > So the queue lock must have been taken outside ub_end_rq(). > > > > But, if ub is calling end_that_request_last() without the queue lock, > > it is a bug in the original code and we should use blk_end_request() > > to fix that. > > So, I have to rewrite ub to split the paths after all, right? > Let's do this then: I'll wait until your patch gets to Linus and > then update it with the split. The reason is, I need the whole > enchilada applied and I don't want to bother tracking iterations > and all the little segments (of which you already have 30). > Until then, ub will have a race by using your original small patch. No. Are you doubting that the current ub code has the problem, aren't you? My patch shouldn't introduce a NEW problem to ub. I have investigated all code paths which call ub_end_rq() in ub.c, and confirmed that ub_end_rq() is always called with the queue lock held. (sc->lock is registered as a queue lock.) So there is no such race in the current ub code. You don't need to rewrite ub. Thanks, Kiyoshi Ueda -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 12/30] blk_end_request: changing ub (take 4)
Hi Pete, On Thu, 13 Dec 2007 13:59:16 -0800, Pete Zaitcev [EMAIL PROTECTED] wrote: - end_that_request_first(rq, uptodate, rq-hard_nr_sectors); - end_that_request_last(rq, uptodate); + if (__blk_end_request(rq, error, blk_rq_bytes(rq))) + BUG(); My understanding was, blk_end_request() is the same thing, only takes the queue lock. But then, should I refactor ub so that it calls __blk_end_request if request function ends with an error and blk_end_request if the end-of-IO even is processed? I'm using __blk_end_request() here and I think it's sufficient, because: o end_that_request_last() must be called with the queue lock held o ub_end_rq() calls end_that_request_last() without taking the queue lock in itself. So the queue lock must have been taken outside ub_end_rq(). But, if ub is calling end_that_request_last() without the queue lock, it is a bug in the original code and we should use blk_end_request() to fix that. So, I have to rewrite ub to split the paths after all, right? Let's do this then: I'll wait until your patch gets to Linus and then update it with the split. The reason is, I need the whole enchilada applied and I don't want to bother tracking iterations and all the little segments (of which you already have 30). Until then, ub will have a race by using your original small patch. No. Are you doubting that the current ub code has the problem, aren't you? My patch shouldn't introduce a NEW problem to ub. I have investigated all code paths which call ub_end_rq() in ub.c, and confirmed that ub_end_rq() is always called with the queue lock held. (sc-lock is registered as a queue lock.) So there is no such race in the current ub code. You don't need to rewrite ub. Thanks, Kiyoshi Ueda -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 12/30] blk_end_request: changing ub (take 4)
On Fri, 14 Dec 2007 12:04:54 -0500 (EST), Kiyoshi Ueda [EMAIL PROTECTED] wrote: I have investigated all code paths which call ub_end_rq() in ub.c, and confirmed that ub_end_rq() is always called with the queue lock held. (sc-lock is registered as a queue lock.) Thanks for reminding me about blk_init_queue, I forgot. Sorry for the confusion. Greetings, -- Pete -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 12/30] blk_end_request: changing ub (take 4)
On Wed, 12 Dec 2007 15:38:15 -0500 (EST), Kiyoshi Ueda <[EMAIL PROTECTED]> wrote: > On Tue, 11 Dec 2007 15:48:03 -0800, Pete Zaitcev <[EMAIL PROTECTED]> wrote: > > > - end_that_request_first(rq, uptodate, rq->hard_nr_sectors); > > > - end_that_request_last(rq, uptodate); > > > + if (__blk_end_request(rq, error, blk_rq_bytes(rq))) > > > + BUG(); > > My understanding was, blk_end_request() is the same thing, only > > takes the queue lock. But then, should I refactor ub so that it > > calls __blk_end_request if request function ends with an error > > and blk_end_request if the end-of-IO even is processed? > I'm using __blk_end_request() here and I think it's sufficient, because: > o end_that_request_last() must be called with the queue lock held > o ub_end_rq() calls end_that_request_last() without taking > the queue lock in itself. > So the queue lock must have been taken outside ub_end_rq(). > But, if ub is calling end_that_request_last() without the queue lock, > it is a bug in the original code and we should use blk_end_request() > to fix that. So, I have to rewrite ub to split the paths after all, right? Let's do this then: I'll wait until your patch gets to Linus and then update it with the split. The reason is, I need the whole enchilada applied and I don't want to bother tracking iterations and all the little segments (of which you already have 30). Until then, ub will have a race by using your original small patch. Best wishes, -- Pete -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 12/30] blk_end_request: changing ub (take 4)
On Wed, 12 Dec 2007 15:38:15 -0500 (EST), Kiyoshi Ueda [EMAIL PROTECTED] wrote: On Tue, 11 Dec 2007 15:48:03 -0800, Pete Zaitcev [EMAIL PROTECTED] wrote: - end_that_request_first(rq, uptodate, rq-hard_nr_sectors); - end_that_request_last(rq, uptodate); + if (__blk_end_request(rq, error, blk_rq_bytes(rq))) + BUG(); My understanding was, blk_end_request() is the same thing, only takes the queue lock. But then, should I refactor ub so that it calls __blk_end_request if request function ends with an error and blk_end_request if the end-of-IO even is processed? I'm using __blk_end_request() here and I think it's sufficient, because: o end_that_request_last() must be called with the queue lock held o ub_end_rq() calls end_that_request_last() without taking the queue lock in itself. So the queue lock must have been taken outside ub_end_rq(). But, if ub is calling end_that_request_last() without the queue lock, it is a bug in the original code and we should use blk_end_request() to fix that. So, I have to rewrite ub to split the paths after all, right? Let's do this then: I'll wait until your patch gets to Linus and then update it with the split. The reason is, I need the whole enchilada applied and I don't want to bother tracking iterations and all the little segments (of which you already have 30). Until then, ub will have a race by using your original small patch. Best wishes, -- Pete -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 12/30] blk_end_request: changing ub (take 4)
Hi Pete, On Tue, 11 Dec 2007 15:48:03 -0800, Pete Zaitcev <[EMAIL PROTECTED]> wrote: > > if (scsi_status == 0) { > > - uptodate = 1; > > + error = 0; > > } else { > > - uptodate = 0; > > + error = -EIO; > > rq->errors = scsi_status; > > } > > - end_that_request_first(rq, uptodate, rq->hard_nr_sectors); > > - end_that_request_last(rq, uptodate); > > + if (__blk_end_request(rq, error, blk_rq_bytes(rq))) > > + BUG(); > > Acked-by: Pete Zaitcev <[EMAIL PROTECTED]> > > I follow the discussion, actually, and wanted to ask someone to look > closer if it's appropriate to use __blk_end_request() here. > My understanding was, blk_end_request() is the same thing, only > takes the queue lock. But then, should I refactor ub so that it > calls __blk_end_request if request function ends with an error > and blk_end_request if the end-of-IO even is processed? If not, > and the above is sufficient, why have blk_end_request at all? The difference between blk_end_request() and __blk_end_request() is whether the queue lock is held or not when end_that_request_last() is called. It's not relevant to the status of the request (error or not). I'm using __blk_end_request() here and I think it's sufficient, because: o end_that_request_last() must be called with the queue lock held o ub_end_rq() calls end_that_request_last() without taking the queue lock in itself. So the queue lock must have been taken outside ub_end_rq(). But, if ub is calling end_that_request_last() without the queue lock, it is a bug in the original code and we should use blk_end_request() to fix that. Does that answer satisfy you? Thanks, Kiyoshi Ueda -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 12/30] blk_end_request: changing ub (take 4)
Hi Pete, On Tue, 11 Dec 2007 15:48:03 -0800, Pete Zaitcev [EMAIL PROTECTED] wrote: if (scsi_status == 0) { - uptodate = 1; + error = 0; } else { - uptodate = 0; + error = -EIO; rq-errors = scsi_status; } - end_that_request_first(rq, uptodate, rq-hard_nr_sectors); - end_that_request_last(rq, uptodate); + if (__blk_end_request(rq, error, blk_rq_bytes(rq))) + BUG(); Acked-by: Pete Zaitcev [EMAIL PROTECTED] I follow the discussion, actually, and wanted to ask someone to look closer if it's appropriate to use __blk_end_request() here. My understanding was, blk_end_request() is the same thing, only takes the queue lock. But then, should I refactor ub so that it calls __blk_end_request if request function ends with an error and blk_end_request if the end-of-IO even is processed? If not, and the above is sufficient, why have blk_end_request at all? The difference between blk_end_request() and __blk_end_request() is whether the queue lock is held or not when end_that_request_last() is called. It's not relevant to the status of the request (error or not). I'm using __blk_end_request() here and I think it's sufficient, because: o end_that_request_last() must be called with the queue lock held o ub_end_rq() calls end_that_request_last() without taking the queue lock in itself. So the queue lock must have been taken outside ub_end_rq(). But, if ub is calling end_that_request_last() without the queue lock, it is a bug in the original code and we should use blk_end_request() to fix that. Does that answer satisfy you? Thanks, Kiyoshi Ueda -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 12/30] blk_end_request: changing ub (take 4)
On Tue, 11 Dec 2007 17:46:47 -0500 (EST), Kiyoshi Ueda <[EMAIL PROTECTED]> wrote: > if (scsi_status == 0) { > - uptodate = 1; > + error = 0; > } else { > - uptodate = 0; > + error = -EIO; > rq->errors = scsi_status; > } > - end_that_request_first(rq, uptodate, rq->hard_nr_sectors); > - end_that_request_last(rq, uptodate); > + if (__blk_end_request(rq, error, blk_rq_bytes(rq))) > + BUG(); Acked-by: Pete Zaitcev <[EMAIL PROTECTED]> I follow the discussion, actually, and wanted to ask someone to look closer if it's appropriate to use __blk_end_request() here. My understanding was, blk_end_request() is the same thing, only takes the queue lock. But then, should I refactor ub so that it calls __blk_end_request if request function ends with an error and blk_end_request if the end-of-IO even is processed? If not, and the above is sufficient, why have blk_end_request at all? -- Pete -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH 12/30] blk_end_request: changing ub (take 4)
This patch converts ub to use blk_end_request interfaces. Related 'uptodate' arguments are converted to 'error'. Cc: Pete Zaitcev <[EMAIL PROTECTED]> Signed-off-by: Kiyoshi Ueda <[EMAIL PROTECTED]> Signed-off-by: Jun'ichi Nomura <[EMAIL PROTECTED]> --- drivers/block/ub.c | 10 +- 1 files changed, 5 insertions(+), 5 deletions(-) Index: 2.6.24-rc4/drivers/block/ub.c === --- 2.6.24-rc4.orig/drivers/block/ub.c +++ 2.6.24-rc4/drivers/block/ub.c @@ -808,16 +808,16 @@ static void ub_rw_cmd_done(struct ub_dev static void ub_end_rq(struct request *rq, unsigned int scsi_status) { - int uptodate; + int error; if (scsi_status == 0) { - uptodate = 1; + error = 0; } else { - uptodate = 0; + error = -EIO; rq->errors = scsi_status; } - end_that_request_first(rq, uptodate, rq->hard_nr_sectors); - end_that_request_last(rq, uptodate); + if (__blk_end_request(rq, error, blk_rq_bytes(rq))) + BUG(); } static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH 12/30] blk_end_request: changing ub (take 4)
This patch converts ub to use blk_end_request interfaces. Related 'uptodate' arguments are converted to 'error'. Cc: Pete Zaitcev [EMAIL PROTECTED] Signed-off-by: Kiyoshi Ueda [EMAIL PROTECTED] Signed-off-by: Jun'ichi Nomura [EMAIL PROTECTED] --- drivers/block/ub.c | 10 +- 1 files changed, 5 insertions(+), 5 deletions(-) Index: 2.6.24-rc4/drivers/block/ub.c === --- 2.6.24-rc4.orig/drivers/block/ub.c +++ 2.6.24-rc4/drivers/block/ub.c @@ -808,16 +808,16 @@ static void ub_rw_cmd_done(struct ub_dev static void ub_end_rq(struct request *rq, unsigned int scsi_status) { - int uptodate; + int error; if (scsi_status == 0) { - uptodate = 1; + error = 0; } else { - uptodate = 0; + error = -EIO; rq-errors = scsi_status; } - end_that_request_first(rq, uptodate, rq-hard_nr_sectors); - end_that_request_last(rq, uptodate); + if (__blk_end_request(rq, error, blk_rq_bytes(rq))) + BUG(); } static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun, -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 12/30] blk_end_request: changing ub (take 4)
On Tue, 11 Dec 2007 17:46:47 -0500 (EST), Kiyoshi Ueda [EMAIL PROTECTED] wrote: if (scsi_status == 0) { - uptodate = 1; + error = 0; } else { - uptodate = 0; + error = -EIO; rq-errors = scsi_status; } - end_that_request_first(rq, uptodate, rq-hard_nr_sectors); - end_that_request_last(rq, uptodate); + if (__blk_end_request(rq, error, blk_rq_bytes(rq))) + BUG(); Acked-by: Pete Zaitcev [EMAIL PROTECTED] I follow the discussion, actually, and wanted to ask someone to look closer if it's appropriate to use __blk_end_request() here. My understanding was, blk_end_request() is the same thing, only takes the queue lock. But then, should I refactor ub so that it calls __blk_end_request if request function ends with an error and blk_end_request if the end-of-IO even is processed? If not, and the above is sufficient, why have blk_end_request at all? -- Pete -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/