The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 5905afc2c7bb713d52c7c7585565feecbb686b44 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023090919-eastcoast-tameness-5f28@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..

Possible dependencies:

5905afc2c7bb ("block: fix pin count management when merging same-page segments") 403b6fb8dac1 ("block: convert bio_map_user_iov to use iov_iter_extract_pages") f62e52d1276b ("iov_iter: Define flags to qualify page extraction.") 7ee4ccf57484 ("block: set FOLL_PCI_P2PDMA in bio_map_user_iov()") 5e3e3f2e15df ("block: set FOLL_PCI_P2PDMA in __bio_iov_iter_get_pages()") d82076403cef ("iov_iter: introduce iov_iter_get_pages_[alloc_]flags()") 91e5adda5cf4 ("block/blk-map: Remove set but unused variable 'added'") e88811bc43b9 ("block: use on-stack page vec for <= UIO_FASTIOV") eba2d3d79829 ("get rid of non-advancing variants") 480cb846c27b ("block: convert to advancing variants of iov_iter_get_pages{,_alloc}()") 3cf42da327f2 ("iov_iter: saner helper for page array allocation") 8520008417c5 ("fold __pipe_get_pages() into pipe_get_pages()") 0aa4fc32f540 ("ITER_XARRAY: don't open-code DIV_ROUND_UP()") 451c0ba9475e ("unify the rest of iov_iter_get_pages()/iov_iter_get_pages_alloc() guts") 68fe506f3731 ("unify xarray_get_pages() and xarray_get_pages_alloc()") acbdeb8320b0 ("unify pipe_get_pages() and pipe_get_pages_alloc()") c81ce28df500 ("iov_iter_get_pages(): sanity-check arguments") 91329559eb07 ("iov_iter_get_pages_alloc(): lift freeing pages array on failure exits into wrapper") 12d426ab64a1 ("ITER_PIPE: fold data_start() and pipe_space_for_user() together") 10f525a8cd7a ("ITER_PIPE: cache the type of last buffer")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 5905afc2c7bb713d52c7c7585565feecbb686b44 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig hch@lst.de Date: Tue, 5 Sep 2023 14:47:31 +0200 Subject: [PATCH] block: fix pin count management when merging same-page segments

There is no need to unpin the added page when adding it to the bio fails as that is done by the loop below. Instead we want to unpin it when adding a single page to the bio more than once as bio_release_pages will only unpin it once.

Fixes: d1916c86ccdc ("block: move same page handling from __bio_add_pc_page to the callers") Signed-off-by: Christoph Hellwig hch@lst.de Reviewed-by: Damien Le Moal dlemoal@kernel.org Link: https://lore.kernel.org/r/20230905124731.328255-1-hch@lst.de Signed-off-by: Jens Axboe axboe@kernel.dk

diff --git a/block/blk-map.c b/block/blk-map.c index 44d74a30ddac..8584babf3ea0 100644 --- a/block/blk-map.c +++ b/block/blk-map.c @@ -315,12 +315,11 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter, n = bytes;

if (!bio_add_hw_page(rq->q, bio, page, n, offs, - max_sectors, &same_page)) { - if (same_page) - bio_release_page(bio, page); + max_sectors, &same_page)) break; - }

+ if (same_page) + bio_release_page(bio, page); bytes -= n; offs = 0; }