From 0ceb331433e8aad9c5f441a965d7c681f8b9046f Mon Sep 17 00:00:00 2001 From: Dmitriy Monakhov Date: Tue, 8 May 2007 00:23:02 -0700 Subject: mm: move common segment checks to separate helper function [akpm@linux-foundation.org: cleanup] Signed-off-by: Monakhov Dmitriy Cc: Christoph Hellwig Acked-by: Anton Altaparmakov Acked-by: David Chinner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/filemap.c | 82 +++++++++++++++++++++++++++++++++--------------------------- 1 file changed, 45 insertions(+), 37 deletions(-) (limited to 'mm/filemap.c') diff --git a/mm/filemap.c b/mm/filemap.c index 5631d6b2a62..3e49fe13d6a 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1110,6 +1110,45 @@ success: return size; } +/* + * Performs necessary checks before doing a write + * @iov: io vector request + * @nr_segs: number of segments in the iovec + * @count: number of bytes to write + * @access_flags: type of access: %VERIFY_READ or %VERIFY_WRITE + * + * Adjust number of segments and amount of bytes to write (nr_segs should be + * properly initialized first). Returns appropriate error code that caller + * should return or zero in case that write should be allowed. + */ +int generic_segment_checks(const struct iovec *iov, + unsigned long *nr_segs, size_t *count, int access_flags) +{ + unsigned long seg; + size_t cnt = 0; + for (seg = 0; seg < *nr_segs; seg++) { + const struct iovec *iv = &iov[seg]; + + /* + * If any segment has a negative length, or the cumulative + * length ever wraps negative then return -EINVAL. + */ + cnt += iv->iov_len; + if (unlikely((ssize_t)(cnt|iv->iov_len) < 0)) + return -EINVAL; + if (access_ok(access_flags, iv->iov_base, iv->iov_len)) + continue; + if (seg == 0) + return -EFAULT; + *nr_segs = seg; + cnt -= iv->iov_len; /* This segment is no good */ + break; + } + *count = cnt; + return 0; +} +EXPORT_SYMBOL(generic_segment_checks); + /** * generic_file_aio_read - generic filesystem read routine * @iocb: kernel I/O control block @@ -1131,24 +1170,9 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, loff_t *ppos = &iocb->ki_pos; count = 0; - for (seg = 0; seg < nr_segs; seg++) { - const struct iovec *iv = &iov[seg]; - - /* - * If any segment has a negative length, or the cumulative - * length ever wraps negative then return -EINVAL. - */ - count += iv->iov_len; - if (unlikely((ssize_t)(count|iv->iov_len) < 0)) - return -EINVAL; - if (access_ok(VERIFY_WRITE, iv->iov_base, iv->iov_len)) - continue; - if (seg == 0) - return -EFAULT; - nr_segs = seg; - count -= iv->iov_len; /* This segment is no good */ - break; - } + retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE); + if (retval) + return retval; /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */ if (filp->f_flags & O_DIRECT) { @@ -2218,30 +2242,14 @@ __generic_file_aio_write_nolock(struct kiocb *iocb, const struct iovec *iov, size_t ocount; /* original count */ size_t count; /* after file limit checks */ struct inode *inode = mapping->host; - unsigned long seg; loff_t pos; ssize_t written; ssize_t err; ocount = 0; - for (seg = 0; seg < nr_segs; seg++) { - const struct iovec *iv = &iov[seg]; - - /* - * If any segment has a negative length, or the cumulative - * length ever wraps negative then return -EINVAL. - */ - ocount += iv->iov_len; - if (unlikely((ssize_t)(ocount|iv->iov_len) < 0)) - return -EINVAL; - if (access_ok(VERIFY_READ, iv->iov_base, iv->iov_len)) - continue; - if (seg == 0) - return -EFAULT; - nr_segs = seg; - ocount -= iv->iov_len; /* This segment is no good */ - break; - } + err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ); + if (err) + return err; count = ocount; pos = *ppos; -- cgit v1.2.3-70-g09d2