Commit 4d53dc99 authored by Maxim Patlasov's avatar Maxim Patlasov Committed by Miklos Szeredi
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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: default avatarMaxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
parent b111c8c0
...@@ -1577,13 +1577,24 @@ static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode, ...@@ -1577,13 +1577,24 @@ static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
unsigned int num; unsigned int num;
unsigned int offset; unsigned int offset;
size_t total_len = 0; 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)) if (IS_ERR(req))
return PTR_ERR(req); return PTR_ERR(req);
offset = outarg->offset & ~PAGE_CACHE_MASK;
req->in.h.opcode = FUSE_NOTIFY_REPLY; req->in.h.opcode = FUSE_NOTIFY_REPLY;
req->in.h.nodeid = outarg->nodeid; req->in.h.nodeid = outarg->nodeid;
req->in.numargs = 2; req->in.numargs = 2;
...@@ -1592,14 +1603,8 @@ static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode, ...@@ -1592,14 +1603,8 @@ static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
req->end = fuse_retrieve_end; req->end = fuse_retrieve_end;
index = outarg->offset >> PAGE_CACHE_SHIFT; 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; struct page *page;
unsigned int this_num; unsigned int this_num;
......
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