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authorMaxim Patlasov <mpatlasov@parallels.com>2012-10-26 19:48:42 +0400
committerMiklos Szeredi <mszeredi@suse.cz>2013-01-24 16:21:26 +0100
commit4d53dc99baf139e4fa0d395f7658032cc2eb3297 (patch)
tree4709fcfd8631d744abc95195a257b67000e863fa /fs/fuse
parentb111c8c0e3e5e780ae0758fc4c1c376a7c9d5997 (diff)
fuse: rework fuse_retrieve()
The patch reworks fuse_retrieve() to allocate only so many page pointers as needed. The core part of the patch is the following calculation: num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; (thanks Miklos for formula). All other changes are mostly shuffling lines. Signed-off-by: Maxim Patlasov <mpatlasov@parallels.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Diffstat (limited to 'fs/fuse')
-rw-r--r--fs/fuse/dev.c25
1 files changed, 15 insertions, 10 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index ff5e8bed5d88..28d9792de4a2 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1577,13 +1577,24 @@ static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
unsigned int num;
unsigned int offset;
size_t total_len = 0;
+ int num_pages;
- req = fuse_get_req(fc, FUSE_MAX_PAGES_PER_REQ);
+ offset = outarg->offset & ~PAGE_CACHE_MASK;
+ file_size = i_size_read(inode);
+
+ num = outarg->size;
+ if (outarg->offset > file_size)
+ num = 0;
+ else if (outarg->offset + num > file_size)
+ num = file_size - outarg->offset;
+
+ num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ);
+
+ req = fuse_get_req(fc, num_pages);
if (IS_ERR(req))
return PTR_ERR(req);
- offset = outarg->offset & ~PAGE_CACHE_MASK;
-
req->in.h.opcode = FUSE_NOTIFY_REPLY;
req->in.h.nodeid = outarg->nodeid;
req->in.numargs = 2;
@@ -1592,14 +1603,8 @@ static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
req->end = fuse_retrieve_end;
index = outarg->offset >> PAGE_CACHE_SHIFT;
- file_size = i_size_read(inode);
- num = outarg->size;
- if (outarg->offset > file_size)
- num = 0;
- else if (outarg->offset + num > file_size)
- num = file_size - outarg->offset;
- while (num && req->num_pages < FUSE_MAX_PAGES_PER_REQ) {
+ while (num && req->num_pages < num_pages) {
struct page *page;
unsigned int this_num;