diff options
| -rw-r--r-- | src/core/refcnt.c | 26 | ||||
| -rw-r--r-- | src/include/ipxe/refcnt.h | 38 |
2 files changed, 52 insertions, 12 deletions
diff --git a/src/core/refcnt.c b/src/core/refcnt.c index e540240f..6117d741 100644 --- a/src/core/refcnt.c +++ b/src/core/refcnt.c @@ -31,18 +31,16 @@ FILE_LICENCE ( GPL2_OR_LATER ); * Increment reference count * * @v refcnt Reference counter, or NULL - * @ret refcnt Reference counter * * If @c refcnt is NULL, no action is taken. */ -struct refcnt * ref_get ( struct refcnt *refcnt ) { +void ref_increment ( struct refcnt *refcnt ) { if ( refcnt ) { - refcnt->refcnt++; + refcnt->count++; DBGC2 ( refcnt, "REFCNT %p incremented to %d\n", - refcnt, refcnt->refcnt ); + refcnt, refcnt->count ); } - return refcnt; } /** @@ -55,18 +53,28 @@ struct refcnt * ref_get ( struct refcnt *refcnt ) { * * If @c refcnt is NULL, no action is taken. */ -void ref_put ( struct refcnt *refcnt ) { +void ref_decrement ( struct refcnt *refcnt ) { if ( ! refcnt ) return; - refcnt->refcnt--; + refcnt->count--; DBGC2 ( refcnt, "REFCNT %p decremented to %d\n", - refcnt, refcnt->refcnt ); + refcnt, refcnt->count ); - if ( refcnt->refcnt >= 0 ) + if ( refcnt->count >= 0 ) return; + if ( refcnt->count < -1 ) { + DBGC ( refcnt, "REFCNT %p decremented too far (%d)!\n", + refcnt, refcnt->count ); + /* Avoid multiple calls to free(), which typically + * result in memory corruption that is very hard to + * track down. + */ + return; + } + if ( refcnt->free ) { DBGC ( refcnt, "REFCNT %p being freed via method %p\n", refcnt, refcnt->free ); diff --git a/src/include/ipxe/refcnt.h b/src/include/ipxe/refcnt.h index 49fce504..0e8b8658 100644 --- a/src/include/ipxe/refcnt.h +++ b/src/include/ipxe/refcnt.h @@ -9,6 +9,9 @@ FILE_LICENCE ( GPL2_OR_LATER ); +#include <stddef.h> +#include <assert.h> + /** * A reference counter * @@ -26,7 +29,7 @@ struct refcnt { * When this count is decremented below zero, the free() * method will be called. */ - int refcnt; + int count; /** Free containing object * * This method is called when the reference count is @@ -75,8 +78,37 @@ ref_init ( struct refcnt *refcnt, .free = free_fn, \ } -extern struct refcnt * ref_get ( struct refcnt *refcnt ); -extern void ref_put ( struct refcnt *refcnt ); +extern void ref_increment ( struct refcnt *refcnt ); +extern void ref_decrement ( struct refcnt *refcnt ); + +/** + * Get additional reference to object + * + * @v refcnt Reference counter, or NULL + * @ret refcnt Reference counter + * + * If @c refcnt is NULL, no action is taken. + */ +#define ref_get( refcnt ) ( { \ + if ( refcnt ) \ + assert ( (refcnt)->count >= 0 ); \ + ref_increment ( refcnt ); \ + (refcnt); } ) + +/** + * Drop reference to object + * + * @v refcnt Reference counter, or NULL + * @ret refcnt Reference counter + * + * If @c refcnt is NULL, no action is taken. + */ +#define ref_put( refcnt ) do { \ + if ( refcnt ) \ + assert ( (refcnt)->count >= 0 ); \ + ref_decrement ( refcnt ); \ + } while ( 0 ) + extern void ref_no_free ( struct refcnt *refcnt ); #endif /* _IPXE_REFCNT_H */ |