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fuse: don't use atomic kmap 

Don't use atomic kmap for mapping userspace buffers in device
read/write/splice.

This is necessary because the next patch (adding store notify)
requires that caller of fuse_copy_page() may sleep between
invocations.  The simplest way to ensure this is to change the atomic
kmaps to non-atomic ones.

Thankfully architectures where kmap() is not a no-op are going out of
fashion, so we can ignore the (probably negligible) performance impact
of this change.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
This commit is contained in:
Miklos Szeredi 2010-07-12 14:41:40 +02:00
parent 815c4163b6
commit 7909b1c640
1 changed files with 5 additions and 5 deletions
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10
fs/fuse/dev.c
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@ -535,13 +535,13 @@ static void fuse_copy_finish(struct fuse_copy_state *cs)
if (!cs->write) {
buf->ops->unmap(cs->pipe, buf, cs->mapaddr);
} else {
kunmap_atomic(cs->mapaddr, KM_USER0);
kunmap(buf->page);
buf->len = PAGE_SIZE - cs->len;
}
cs->currbuf = NULL;
cs->mapaddr = NULL;
} else if (cs->mapaddr) {
kunmap_atomic(cs->mapaddr, KM_USER0);
kunmap(cs->pg);
if (cs->write) {
flush_dcache_page(cs->pg);
set_page_dirty_lock(cs->pg);
@ -572,7 +572,7 @@ static int fuse_copy_fill(struct fuse_copy_state *cs)
BUG_ON(!cs->nr_segs);
cs->currbuf = buf;
cs->mapaddr = buf->ops->map(cs->pipe, buf, 1);
cs->mapaddr = buf->ops->map(cs->pipe, buf, 0);
cs->len = buf->len;
cs->buf = cs->mapaddr + buf->offset;
cs->pipebufs++;
@ -592,7 +592,7 @@ static int fuse_copy_fill(struct fuse_copy_state *cs)
buf->len = 0;
cs->currbuf = buf;
cs->mapaddr = kmap_atomic(page, KM_USER0);
cs->mapaddr = kmap(page);
cs->buf = cs->mapaddr;
cs->len = PAGE_SIZE;
cs->pipebufs++;
@ -611,7 +611,7 @@ static int fuse_copy_fill(struct fuse_copy_state *cs)
return err;
BUG_ON(err != 1);
offset = cs->addr % PAGE_SIZE;
cs->mapaddr = kmap_atomic(cs->pg, KM_USER0);
cs->mapaddr = kmap(cs->pg);
cs->buf = cs->mapaddr + offset;
cs->len = min(PAGE_SIZE - offset, cs->seglen);
cs->seglen -= cs->len;