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Diffstat (limited to '')
| -rw-r--r-- | fs/nfs/pagelist.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index cbdd1c6aaa94..c5bb51a29e80 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -355,6 +355,26 @@ void nfs_pageio_complete(struct nfs_pageio_descriptor *desc) nfs_pageio_doio(desc); } +/** + * nfs_pageio_cond_complete - Conditional I/O completion + * @desc: pointer to io descriptor + * @index: page index + * + * It is important to ensure that processes don't try to take locks + * on non-contiguous ranges of pages as that might deadlock. This + * function should be called before attempting to wait on a locked + * nfs_page. It will complete the I/O if the page index 'index' + * is not contiguous with the existing list of pages in 'desc'. + */ +void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index) +{ + if (!list_empty(&desc->pg_list)) { + struct nfs_page *prev = nfs_list_entry(desc->pg_list.prev); + if (index != prev->wb_index + 1) + nfs_pageio_doio(desc); + } +} + #define NFS_SCAN_MAXENTRIES 16 /** * nfs_scan_list - Scan a list for matching requests |