diff options
| author | Michael Brown <mcb30@etherboot.org> | 2009-02-01 18:02:28 +0000 |
|---|---|---|
| committer | Michael Brown <mcb30@etherboot.org> | 2009-02-01 20:16:10 +0000 |
| commit | dbe84c5aad583a4194666d2d925a5cda53852631 (patch) | |
| tree | 401417d56c1f4108345c1489d40c68bf6c098cf7 /src/net/udp | |
| parent | 017109821234608d842a7999eef76545299ff2a4 (diff) | |
| download | ipxe-dbe84c5aad583a4194666d2d925a5cda53852631.tar.gz | |
[iobuf] Add iob_disown() and use it where it simplifies code
There are many functions that take ownership of the I/O buffer they
are passed as a parameter. The caller should not retain a pointer to
the I/O buffer. Use iob_disown() to automatically nullify the
caller's pointer, e.g.:
xfer_deliver_iob ( xfer, iob_disown ( iobuf ) );
This will ensure that iobuf is set to NULL for any code after the call
to xfer_deliver_iob().
iob_disown() is currently used only in places where it simplifies the
code, by avoiding an extra line explicitly setting the I/O buffer
pointer to NULL. It should ideally be used with each call to any
function that takes ownership of an I/O buffer. (The SSA
optimisations will ensure that use of iob_disown() gets optimised away
in cases where the caller makes no further use of the I/O buffer
pointer anyway.)
If gcc ever introduces an __attribute__((free)), indicating that use
of a function argument after a function call should generate a
warning, then we should use this to identify all applicable function
call sites, and add iob_disown() as necessary.
Diffstat (limited to 'src/net/udp')
| -rw-r--r-- | src/net/udp/dhcp.c | 5 | ||||
| -rw-r--r-- | src/net/udp/tftp.c | 8 |
2 files changed, 5 insertions, 8 deletions
diff --git a/src/net/udp/dhcp.c b/src/net/udp/dhcp.c index 26c50172..6ebf6021 100644 --- a/src/net/udp/dhcp.c +++ b/src/net/udp/dhcp.c @@ -976,9 +976,8 @@ static int dhcp_tx ( struct dhcp_session *dhcp ) { /* Transmit the packet */ iob_put ( iobuf, dhcppkt.len ); - rc = xfer_deliver_iob_meta ( &dhcp->xfer, iobuf, &meta ); - iobuf = NULL; - if ( rc != 0 ) { + if ( ( rc = xfer_deliver_iob_meta ( &dhcp->xfer, iob_disown ( iobuf ), + &meta ) ) != 0 ) { DBGC ( dhcp, "DHCP %p could not transmit UDP packet: %s\n", dhcp, strerror ( rc ) ); goto done; diff --git a/src/net/udp/tftp.c b/src/net/udp/tftp.c index 13734b0f..ec6b1b40 100644 --- a/src/net/udp/tftp.c +++ b/src/net/udp/tftp.c @@ -763,9 +763,8 @@ static int tftp_rx_data ( struct tftp_request *tftp, memset ( &meta, 0, sizeof ( meta ) ); meta.whence = SEEK_SET; meta.offset = offset; - rc = xfer_deliver_iob_meta ( &tftp->xfer, iobuf, &meta ); - iobuf = NULL; - if ( rc != 0 ) { + if ( ( rc = xfer_deliver_iob_meta ( &tftp->xfer, iob_disown ( iobuf ), + &meta ) ) != 0 ) { DBGC ( tftp, "TFTP %p could not deliver data: %s\n", tftp, strerror ( rc ) ); goto done; @@ -887,8 +886,7 @@ static int tftp_rx ( struct tftp_request *tftp, rc = tftp_rx_oack ( tftp, iobuf->data, len ); break; case htons ( TFTP_DATA ): - rc = tftp_rx_data ( tftp, iobuf ); - iobuf = NULL; + rc = tftp_rx_data ( tftp, iob_disown ( iobuf ) ); break; case htons ( TFTP_ERROR ): rc = tftp_rx_error ( tftp, iobuf->data, len ); |