* Re: [PATCH 7/7] iov_iter: remove iov_iter_is_aligned [not found] ` <20250801234736.1913170-8-kbusch@meta.com> @ 2025-08-02 2:02 ` Mike Snitzer 2025-08-04 14:16 ` Keith Busch 0 siblings, 1 reply; 6+ messages in thread From: Mike Snitzer @ 2025-08-02 2:02 UTC (permalink / raw) To: Keith Busch Cc: linux-block, linux-fsdevel, linux-kernel, axboe, dw, brauner, Keith Busch, Chuck Lever, linux-nfs On Fri, Aug 01, 2025 at 04:47:36PM -0700, Keith Busch wrote: > From: Keith Busch <kbusch@kernel.org> > > No more callers. > > Signed-off-by: Keith Busch <kbusch@kernel.org> You had me up until this last patch. I'm actually making use of iov_iter_is_aligned() in a series of changes for both NFS and NFSD. Chuck has included some of the NFSD changes in his nfsd-testing branch, see: https://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git/commit/?h=nfsd-testing&id=5d78ac1e674b45f9c9e3769b48efb27c44f4e4d3 And the balance of my work that is pending review/inclusion is: https://lore.kernel.org/linux-nfs/20250731230633.89983-1-snitzer@kernel.org/ https://lore.kernel.org/linux-nfs/20250801171049.94235-1-snitzer@kernel.org/ I only need iov_iter_aligned_bvec, but recall I want to relax its checking with this patch: https://lore.kernel.org/linux-nfs/20250708160619.64800-5-snitzer@kernel.org/ Should I just add iov_iter_aligned_bvec() to fs/nfs_common/ so that both NFS and NFSD can use it? Thanks, Mike > --- > include/linux/uio.h | 2 - > lib/iov_iter.c | 95 --------------------------------------------- > 2 files changed, 97 deletions(-) > > diff --git a/include/linux/uio.h b/include/linux/uio.h > index 2e86c653186c6..5b127043a1519 100644 > --- a/include/linux/uio.h > +++ b/include/linux/uio.h > @@ -286,8 +286,6 @@ size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i); > #endif > > size_t iov_iter_zero(size_t bytes, struct iov_iter *); > -bool iov_iter_is_aligned(const struct iov_iter *i, unsigned addr_mask, > - unsigned len_mask); > unsigned long iov_iter_alignment(const struct iov_iter *i); > unsigned long iov_iter_gap_alignment(const struct iov_iter *i); > void iov_iter_init(struct iov_iter *i, unsigned int direction, const struct iovec *iov, > diff --git a/lib/iov_iter.c b/lib/iov_iter.c > index f9193f952f499..2fe66a6b8789e 100644 > --- a/lib/iov_iter.c > +++ b/lib/iov_iter.c > @@ -784,101 +784,6 @@ void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) > } > EXPORT_SYMBOL(iov_iter_discard); > > -static bool iov_iter_aligned_iovec(const struct iov_iter *i, unsigned addr_mask, > - unsigned len_mask) > -{ > - const struct iovec *iov = iter_iov(i); > - size_t size = i->count; > - size_t skip = i->iov_offset; > - > - do { > - size_t len = iov->iov_len - skip; > - > - if (len > size) > - len = size; > - if (len & len_mask) > - return false; > - if ((unsigned long)(iov->iov_base + skip) & addr_mask) > - return false; > - > - iov++; > - size -= len; > - skip = 0; > - } while (size); > - > - return true; > -} > - > -static bool iov_iter_aligned_bvec(const struct iov_iter *i, unsigned addr_mask, > - unsigned len_mask) > -{ > - const struct bio_vec *bvec = i->bvec; > - unsigned skip = i->iov_offset; > - size_t size = i->count; > - > - do { > - size_t len = bvec->bv_len - skip; > - > - if (len > size) > - len = size; > - if (len & len_mask) > - return false; > - if ((unsigned long)(bvec->bv_offset + skip) & addr_mask) > - return false; > - > - bvec++; > - size -= len; > - skip = 0; > - } while (size); > - > - return true; > -} > - > -/** > - * iov_iter_is_aligned() - Check if the addresses and lengths of each segments > - * are aligned to the parameters. > - * > - * @i: &struct iov_iter to restore > - * @addr_mask: bit mask to check against the iov element's addresses > - * @len_mask: bit mask to check against the iov element's lengths > - * > - * Return: false if any addresses or lengths intersect with the provided masks > - */ > -bool iov_iter_is_aligned(const struct iov_iter *i, unsigned addr_mask, > - unsigned len_mask) > -{ > - if (likely(iter_is_ubuf(i))) { > - if (i->count & len_mask) > - return false; > - if ((unsigned long)(i->ubuf + i->iov_offset) & addr_mask) > - return false; > - return true; > - } > - > - if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) > - return iov_iter_aligned_iovec(i, addr_mask, len_mask); > - > - if (iov_iter_is_bvec(i)) > - return iov_iter_aligned_bvec(i, addr_mask, len_mask); > - > - /* With both xarray and folioq types, we're dealing with whole folios. */ > - if (iov_iter_is_xarray(i)) { > - if (i->count & len_mask) > - return false; > - if ((i->xarray_start + i->iov_offset) & addr_mask) > - return false; > - } > - if (iov_iter_is_folioq(i)) { > - if (i->count & len_mask) > - return false; > - if (i->iov_offset & addr_mask) > - return false; > - } > - > - return true; > -} > -EXPORT_SYMBOL_GPL(iov_iter_is_aligned); > - > static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) > { > const struct iovec *iov = iter_iov(i); > -- > 2.47.3 > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 7/7] iov_iter: remove iov_iter_is_aligned 2025-08-02 2:02 ` [PATCH 7/7] iov_iter: remove iov_iter_is_aligned Mike Snitzer @ 2025-08-04 14:16 ` Keith Busch 2025-08-04 15:25 ` Mike Snitzer 0 siblings, 1 reply; 6+ messages in thread From: Keith Busch @ 2025-08-04 14:16 UTC (permalink / raw) To: Mike Snitzer Cc: Keith Busch, linux-block, linux-fsdevel, linux-kernel, axboe, dw, brauner, Chuck Lever, linux-nfs On Fri, Aug 01, 2025 at 10:02:49PM -0400, Mike Snitzer wrote: > On Fri, Aug 01, 2025 at 04:47:36PM -0700, Keith Busch wrote: > > From: Keith Busch <kbusch@kernel.org> > > > > No more callers. > > > > Signed-off-by: Keith Busch <kbusch@kernel.org> > > You had me up until this last patch. > > I'm actually making use of iov_iter_is_aligned() in a series of > changes for both NFS and NFSD. Chuck has included some of the > NFSD changes in his nfsd-testing branch, see: > https://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git/commit/?h=nfsd-testing&id=5d78ac1e674b45f9c9e3769b48efb27c44f4e4d3 > > And the balance of my work that is pending review/inclusion is: > https://lore.kernel.org/linux-nfs/20250731230633.89983-1-snitzer@kernel.org/ > https://lore.kernel.org/linux-nfs/20250801171049.94235-1-snitzer@kernel.org/ > > I only need iov_iter_aligned_bvec, but recall I want to relax its > checking with this patch: > https://lore.kernel.org/linux-nfs/20250708160619.64800-5-snitzer@kernel.org/ > > Should I just add iov_iter_aligned_bvec() to fs/nfs_common/ so that > both NFS and NFSD can use it? If at all possible, I recommend finding a place that already walks the vectors and do an opprotunistic check for the alignments there. This will save CPU cycles. For example, nfsd_iter_read already iterates the bvec while setting each page. Could you check the alignment while doing that instead of iterating a second time immediately after? ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 7/7] iov_iter: remove iov_iter_is_aligned 2025-08-04 14:16 ` Keith Busch @ 2025-08-04 15:25 ` Mike Snitzer 2025-08-04 15:27 ` Mike Snitzer 2025-08-04 22:26 ` Mike Snitzer 0 siblings, 2 replies; 6+ messages in thread From: Mike Snitzer @ 2025-08-04 15:25 UTC (permalink / raw) To: Keith Busch Cc: Keith Busch, linux-block, linux-fsdevel, linux-kernel, axboe, dw, brauner, Chuck Lever, linux-nfs On Mon, Aug 04, 2025 at 08:16:39AM -0600, Keith Busch wrote: > On Fri, Aug 01, 2025 at 10:02:49PM -0400, Mike Snitzer wrote: > > On Fri, Aug 01, 2025 at 04:47:36PM -0700, Keith Busch wrote: > > > From: Keith Busch <kbusch@kernel.org> > > > > > > No more callers. > > > > > > Signed-off-by: Keith Busch <kbusch@kernel.org> > > > > You had me up until this last patch. > > > > I'm actually making use of iov_iter_is_aligned() in a series of > > changes for both NFS and NFSD. Chuck has included some of the > > NFSD changes in his nfsd-testing branch, see: > > https://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git/commit/?h=nfsd-testing&id=5d78ac1e674b45f9c9e3769b48efb27c44f4e4d3 > > > > And the balance of my work that is pending review/inclusion is: > > https://lore.kernel.org/linux-nfs/20250731230633.89983-1-snitzer@kernel.org/ > > https://lore.kernel.org/linux-nfs/20250801171049.94235-1-snitzer@kernel.org/ > > > > I only need iov_iter_aligned_bvec, but recall I want to relax its > > checking with this patch: > > https://lore.kernel.org/linux-nfs/20250708160619.64800-5-snitzer@kernel.org/ > > > > Should I just add iov_iter_aligned_bvec() to fs/nfs_common/ so that > > both NFS and NFSD can use it? > > If at all possible, I recommend finding a place that already walks the > vectors and do an opprotunistic check for the alignments there. This > will save CPU cycles. For example, nfsd_iter_read already iterates the > bvec while setting each page. Could you check the alignment while doing > that instead of iterating a second time immediately after? Nice goal, I'll see if I can pull it off. I'm currently using iov_iter_is_aligned() in 3 new call sites (for READ and WRITE) in both NFS and NFSD: nfs_local_iter_init, nfsd_iter_read, nfsd_vfs_write nfsd_vfs_write is the only one that doesn't iterate the bvec as-is, but it does work that _should_ obviate the need to doable check the alignment. ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 7/7] iov_iter: remove iov_iter_is_aligned 2025-08-04 15:25 ` Mike Snitzer @ 2025-08-04 15:27 ` Mike Snitzer 2025-08-04 22:26 ` Mike Snitzer 1 sibling, 0 replies; 6+ messages in thread From: Mike Snitzer @ 2025-08-04 15:27 UTC (permalink / raw) To: Keith Busch Cc: Keith Busch, linux-block, linux-fsdevel, linux-kernel, axboe, dw, brauner, Chuck Lever, linux-nfs On Mon, Aug 04, 2025 at 11:25:08AM -0400, Mike Snitzer wrote: > On Mon, Aug 04, 2025 at 08:16:39AM -0600, Keith Busch wrote: > > On Fri, Aug 01, 2025 at 10:02:49PM -0400, Mike Snitzer wrote: > > > On Fri, Aug 01, 2025 at 04:47:36PM -0700, Keith Busch wrote: > > > > From: Keith Busch <kbusch@kernel.org> > > > > > > > > No more callers. > > > > > > > > Signed-off-by: Keith Busch <kbusch@kernel.org> > > > > > > You had me up until this last patch. > > > > > > I'm actually making use of iov_iter_is_aligned() in a series of > > > changes for both NFS and NFSD. Chuck has included some of the > > > NFSD changes in his nfsd-testing branch, see: > > > https://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git/commit/?h=nfsd-testing&id=5d78ac1e674b45f9c9e3769b48efb27c44f4e4d3 > > > > > > And the balance of my work that is pending review/inclusion is: > > > https://lore.kernel.org/linux-nfs/20250731230633.89983-1-snitzer@kernel.org/ > > > https://lore.kernel.org/linux-nfs/20250801171049.94235-1-snitzer@kernel.org/ > > > > > > I only need iov_iter_aligned_bvec, but recall I want to relax its > > > checking with this patch: > > > https://lore.kernel.org/linux-nfs/20250708160619.64800-5-snitzer@kernel.org/ > > > > > > Should I just add iov_iter_aligned_bvec() to fs/nfs_common/ so that > > > both NFS and NFSD can use it? > > > > If at all possible, I recommend finding a place that already walks the > > vectors and do an opprotunistic check for the alignments there. This > > will save CPU cycles. For example, nfsd_iter_read already iterates the > > bvec while setting each page. Could you check the alignment while doing > > that instead of iterating a second time immediately after? > > Nice goal, I'll see if I can pull it off. > > I'm currently using iov_iter_is_aligned() in 3 new call sites (for > READ and WRITE) in both NFS and NFSD: nfs_local_iter_init, > nfsd_iter_read, nfsd_vfs_write > > nfsd_vfs_write is the only one that doesn't iterate the bvec as-is, > but it does work that _should_ obviate the need to doable check the > alignment. Freudian typo: s/doable/double/ :) ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 7/7] iov_iter: remove iov_iter_is_aligned 2025-08-04 15:25 ` Mike Snitzer 2025-08-04 15:27 ` Mike Snitzer @ 2025-08-04 22:26 ` Mike Snitzer 2025-08-04 22:57 ` Keith Busch 1 sibling, 1 reply; 6+ messages in thread From: Mike Snitzer @ 2025-08-04 22:26 UTC (permalink / raw) To: Keith Busch Cc: Keith Busch, linux-block, linux-fsdevel, linux-kernel, axboe, dw, brauner, Chuck Lever, linux-nfs On Mon, Aug 04, 2025 at 11:25:08AM -0400, Mike Snitzer wrote: > On Mon, Aug 04, 2025 at 08:16:39AM -0600, Keith Busch wrote: > > On Fri, Aug 01, 2025 at 10:02:49PM -0400, Mike Snitzer wrote: > > > On Fri, Aug 01, 2025 at 04:47:36PM -0700, Keith Busch wrote: > > > > From: Keith Busch <kbusch@kernel.org> > > > > > > > > No more callers. > > > > > > > > Signed-off-by: Keith Busch <kbusch@kernel.org> > > > > > > You had me up until this last patch. > > > > > > I'm actually making use of iov_iter_is_aligned() in a series of > > > changes for both NFS and NFSD. Chuck has included some of the > > > NFSD changes in his nfsd-testing branch, see: > > > https://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git/commit/?h=nfsd-testing&id=5d78ac1e674b45f9c9e3769b48efb27c44f4e4d3 > > > > > > And the balance of my work that is pending review/inclusion is: > > > https://lore.kernel.org/linux-nfs/20250731230633.89983-1-snitzer@kernel.org/ > > > https://lore.kernel.org/linux-nfs/20250801171049.94235-1-snitzer@kernel.org/ > > > > > > I only need iov_iter_aligned_bvec, but recall I want to relax its > > > checking with this patch: > > > https://lore.kernel.org/linux-nfs/20250708160619.64800-5-snitzer@kernel.org/ > > > > > > Should I just add iov_iter_aligned_bvec() to fs/nfs_common/ so that > > > both NFS and NFSD can use it? > > > > If at all possible, I recommend finding a place that already walks the > > vectors and do an opprotunistic check for the alignments there. This > > will save CPU cycles. For example, nfsd_iter_read already iterates the > > bvec while setting each page. Could you check the alignment while doing > > that instead of iterating a second time immediately after? > > Nice goal, I'll see if I can pull it off. > > I'm currently using iov_iter_is_aligned() in 3 new call sites (for > READ and WRITE) in both NFS and NFSD: nfs_local_iter_init, > nfsd_iter_read, nfsd_vfs_write > > nfsd_vfs_write is the only one that doesn't iterate the bvec as-is, > but it does work that _should_ obviate the need to doable check the > alignment. FYI, I was able to avoid using iov_iter_is_aligned() in favor of checks in earlier code (in both NFSD and NFS). Thanks, Mike ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 7/7] iov_iter: remove iov_iter_is_aligned 2025-08-04 22:26 ` Mike Snitzer @ 2025-08-04 22:57 ` Keith Busch 0 siblings, 0 replies; 6+ messages in thread From: Keith Busch @ 2025-08-04 22:57 UTC (permalink / raw) To: Mike Snitzer Cc: Keith Busch, linux-block, linux-fsdevel, linux-kernel, axboe, dw, brauner, Chuck Lever, linux-nfs On Mon, Aug 04, 2025 at 06:26:55PM -0400, Mike Snitzer wrote: > FYI, I was able to avoid using iov_iter_is_aligned() in favor of > checks in earlier code (in both NFSD and NFS). Excellent! I promise removing the extra iteration is totally worth it. ;) I just know of one error case bug mentioned in patch 2, so unless I hear anything else, I'll spin out the new version with a fix for just that tomorrow. ^ permalink raw reply [flat|nested] 6+ messages in thread
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2025-08-02 2:02 ` [PATCH 7/7] iov_iter: remove iov_iter_is_aligned Mike Snitzer
2025-08-04 14:16 ` Keith Busch
2025-08-04 15:25 ` Mike Snitzer
2025-08-04 15:27 ` Mike Snitzer
2025-08-04 22:26 ` Mike Snitzer
2025-08-04 22:57 ` Keith Busch
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