diff options
| author | Baolin Wang <baolin.wang@linux.alibaba.com> | 2024-10-26 21:51:52 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-11-06 20:11:18 -0800 |
| commit | 729881ffd390797077cec0e573d33b4d724d70b3 (patch) | |
| tree | ed311cd0da942c93a0234437e873666e15e53ff6 /mm/shmem.c | |
| parent | 477327e10639a1ec5698847030b494dc75de33e4 (diff) | |
mm: shmem: fallback to page size splice if large folio has poisoned pages
The tmpfs has already supported the PMD-sized large folios, and splice()
can not read any pages if the large folio has a poisoned page, which is
not good as Matthew pointed out in a previous email[1]:
"so if we have hwpoison set on one page in a folio, we now can't read
bytes from any page in the folio? That seems like we've made a bad
situation worse."
Thus add a fallback to the PAGE_SIZE splice() still allows reading normal
pages if the large folio has hwpoisoned pages.
[1] https://lore.kernel.org/all/Zw_d0EVAJkpNJEbA@casper.infradead.org/
[baolin.wang@linux.alibaba.com: code layout cleaup, per dhowells]
Link: https://lkml.kernel.org/r/32dd938c-3531-49f7-93e4-b7ff21fec569@linux.alibaba.com
Link: https://lkml.kernel.org/r/e3737fbd5366c4de4337bf5f2044817e77a5235b.1729915173.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/shmem.c')
| -rw-r--r-- | mm/shmem.c | 38 |
1 files changed, 30 insertions, 8 deletions
diff --git a/mm/shmem.c b/mm/shmem.c index 06da05f984da..5afc5b1f7ae1 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -3288,11 +3288,16 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos, len = min_t(size_t, len, npages * PAGE_SIZE); do { + bool fallback_page_splice = false; + struct page *page = NULL; + pgoff_t index; + size_t size; + if (*ppos >= i_size_read(inode)) break; - error = shmem_get_folio(inode, *ppos / PAGE_SIZE, 0, &folio, - SGP_READ); + index = *ppos >> PAGE_SHIFT; + error = shmem_get_folio(inode, index, 0, &folio, SGP_READ); if (error) { if (error == -EINVAL) error = 0; @@ -3301,12 +3306,15 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos, if (folio) { folio_unlock(folio); - if (folio_test_hwpoison(folio) || - (folio_test_large(folio) && - folio_test_has_hwpoisoned(folio))) { + page = folio_file_page(folio, index); + if (PageHWPoison(page)) { error = -EIO; break; } + + if (folio_test_large(folio) && + folio_test_has_hwpoisoned(folio)) + fallback_page_splice = true; } /* @@ -3320,7 +3328,17 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos, isize = i_size_read(inode); if (unlikely(*ppos >= isize)) break; - part = min_t(loff_t, isize - *ppos, len); + /* + * Fallback to PAGE_SIZE splice if the large folio has hwpoisoned + * pages. + */ + size = len; + if (unlikely(fallback_page_splice)) { + size_t offset = *ppos & ~PAGE_MASK; + + size = umin(size, PAGE_SIZE - offset); + } + part = min_t(loff_t, isize - *ppos, size); if (folio) { /* @@ -3328,8 +3346,12 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos, * virtual addresses, take care about potential aliasing * before reading the page on the kernel side. */ - if (mapping_writably_mapped(mapping)) - flush_dcache_folio(folio); + if (mapping_writably_mapped(mapping)) { + if (likely(!fallback_page_splice)) + flush_dcache_folio(folio); + else + flush_dcache_page(page); + } folio_mark_accessed(folio); /* * Ok, we have the page, and it's up-to-date, so we can |