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[PATCH] splice: cleanup the SPLICE_F_NONBLOCK handling 

- generic_file_splice_read() more readable and correct
- Don't bail on page allocation with NONBLOCK set, just don't allow
  direct blocking on IO (eg lock_page).

Signed-off-by: Jens Axboe <axboe@suse.de>
This commit is contained in:
Jens Axboe 2006-04-19 15:56:12 +02:00
parent 91ad66ef44
commit c4f895cbe1
1 changed files with 16 additions and 14 deletions
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30
fs/splice.c
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@ -278,14 +278,6 @@ find_page:
*/ */
page = find_get_page(mapping, index); page = find_get_page(mapping, index);
if (!page) { if (!page) {
/*
* If in nonblock mode then dont block on
* readpage (we've kicked readahead so there
* will be asynchronous progress):
*/
if (flags & SPLICE_F_NONBLOCK)
break;
/* /*
* page didn't exist, allocate one * page didn't exist, allocate one
*/ */
@ -307,6 +299,13 @@ find_page:
* If the page isn't uptodate, we may need to start io on it * If the page isn't uptodate, we may need to start io on it
*/ */
if (!PageUptodate(page)) { if (!PageUptodate(page)) {
/*
* If in nonblock mode then dont block on waiting
* for an in-flight io page
*/
if (flags & SPLICE_F_NONBLOCK)
break;
lock_page(page); lock_page(page);
/* /*
@ -400,17 +399,20 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
while (len) { while (len) {
ret = __generic_file_splice_read(in, ppos, pipe, len, flags); ret = __generic_file_splice_read(in, ppos, pipe, len, flags);
if (ret <= 0) if (ret < 0)
break; break;
else if (!ret) {
if (spliced)
break;
if (flags & SPLICE_F_NONBLOCK) {
ret = -EAGAIN;
break;
}
}
*ppos += ret; *ppos += ret;
len -= ret; len -= ret;
spliced += ret; spliced += ret;
if (!(flags & SPLICE_F_NONBLOCK))
continue;
ret = -EAGAIN;
break;
} }
if (spliced) if (spliced)