From: Fushuai Wang Date: Tue, 7 Oct 2025 08:26:03 +0000 (+0800) Subject: cifs: Fix copy_to_iter return value check X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=0cc380d0e1d36b8f2703379890e90f896f68e9e8;p=users%2Fhch%2Fmisc.git cifs: Fix copy_to_iter return value check The return value of copy_to_iter() function will never be negative, it is the number of bytes copied, or zero if nothing was copied. Update the check to treat 0 as an error, and return -1 in that case. Fixes: d08089f649a0 ("cifs: Change the I/O paths to use an iterator rather than a page list") Acked-by: Tom Talpey Reviewed-by: David Howells Signed-off-by: Fushuai Wang Signed-off-by: Steve French --- diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c index 80114292e2c9..83d9cde8a718 100644 --- a/fs/smb/client/smb2ops.c +++ b/fs/smb/client/smb2ops.c @@ -4736,7 +4736,7 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid, unsigned int pad_len; struct cifs_io_subrequest *rdata = mid->callback_data; struct smb2_hdr *shdr = (struct smb2_hdr *)buf; - int length; + size_t copied; bool use_rdma_mr = false; if (shdr->Command != SMB2_READ) { @@ -4849,10 +4849,10 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid, } else if (buf_len >= data_offset + data_len) { /* read response payload is in buf */ WARN_ONCE(buffer, "read data can be either in buf or in buffer"); - length = copy_to_iter(buf + data_offset, data_len, &rdata->subreq.io_iter); - if (length < 0) - return length; - rdata->got_bytes = data_len; + copied = copy_to_iter(buf + data_offset, data_len, &rdata->subreq.io_iter); + if (copied == 0) + return -EIO; + rdata->got_bytes = copied; } else { /* read response payload cannot be in both buf and pages */ WARN_ONCE(1, "buf can not contain only a part of read data");