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authorArpad Horvath <secracon@gmail.com>2014-02-14 16:42:27 -0800
committerJP Abgrall <jpa@google.com>2014-02-14 16:50:27 -0800
commit80b435a3f35795600654e9705f4b3fbbcc427a9d (patch)
tree4dd4f4f5cb43c520464070a8a3188691f652fab9 /sdcard
parentd0307beeef57b9db06b82f1ffba746c5decb0b72 (diff)
sdcard: direct I/O file access fix
If a file is opened in direct I/O mode (with O_DIRECT flag), the read buffer addess must be aligned to memory page size boundary. The Direct I/O is not needed for normal files, however, some special hardware access (e.g. smart SD cards) will not work without it. Change-Id: I42babeee86dba1880fd23e2592fddd7060da3e20
Diffstat (limited to 'sdcard')
-rw-r--r--sdcard/sdcard.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/sdcard/sdcard.c b/sdcard/sdcard.c
index 4722708f3..3bc8cd3f7 100644
--- a/sdcard/sdcard.c
+++ b/sdcard/sdcard.c
@@ -232,7 +232,7 @@ struct fuse_handler {
* buffer at the same time. This allows us to share the underlying storage. */
union {
__u8 request_buffer[MAX_REQUEST_SIZE];
- __u8 read_buffer[MAX_READ];
+ __u8 read_buffer[MAX_READ + PAGESIZE];
};
};
@@ -1218,6 +1218,7 @@ static int handle_read(struct fuse* fuse, struct fuse_handler* handler,
__u32 size = req->size;
__u64 offset = req->offset;
int res;
+ __u8 *read_buffer = (__u8 *) ((uintptr_t)(handler->read_buffer + PAGESIZE) & ~((uintptr_t)PAGESIZE-1));
/* Don't access any other fields of hdr or req beyond this point, the read buffer
* overlaps the request buffer and will clobber data in the request. This
@@ -1225,14 +1226,14 @@ static int handle_read(struct fuse* fuse, struct fuse_handler* handler,
TRACE("[%d] READ %p(%d) %u@%llu\n", handler->token,
h, h->fd, size, offset);
- if (size > sizeof(handler->read_buffer)) {
+ if (size > MAX_READ) {
return -EINVAL;
}
- res = pread64(h->fd, handler->read_buffer, size, offset);
+ res = pread64(h->fd, read_buffer, size, offset);
if (res < 0) {
return -errno;
}
- fuse_reply(fuse, unique, handler->read_buffer, res);
+ fuse_reply(fuse, unique, read_buffer, res);
return NO_STATUS;
}