Loading fs/fcntl.c +66 −36 Original line number Diff line number Diff line Loading @@ -618,60 +618,90 @@ static DEFINE_RWLOCK(fasync_lock); static struct kmem_cache *fasync_cache __read_mostly; /* * fasync_helper() is used by almost all character device drivers * to set up the fasync queue. It returns negative on error, 0 if it did * no changes and positive if it added/deleted the entry. * Remove a fasync entry. If successfully removed, return * positive and clear the FASYNC flag. If no entry exists, * do nothing and return 0. * * NOTE! It is very important that the FASYNC flag always * match the state "is the filp on a fasync list". * * We always take the 'filp->f_lock', in since fasync_lock * needs to be irq-safe. */ int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) static int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp) { struct fasync_struct *fa, **fp; struct fasync_struct *new = NULL; int result = 0; if (on) { new = kmem_cache_alloc(fasync_cache, GFP_KERNEL); if (!new) return -ENOMEM; spin_lock(&filp->f_lock); write_lock_irq(&fasync_lock); for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { if (fa->fa_file != filp) continue; *fp = fa->fa_next; kmem_cache_free(fasync_cache, fa); filp->f_flags &= ~FASYNC; result = 1; break; } write_unlock_irq(&fasync_lock); spin_unlock(&filp->f_lock); return result; } /* * We need to take f_lock first since it's not an IRQ-safe * lock. * Add a fasync entry. Return negative on error, positive if * added, and zero if did nothing but change an existing one. * * NOTE! It is very important that the FASYNC flag always * match the state "is the filp on a fasync list". */ static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp) { struct fasync_struct *new, *fa, **fp; int result = 0; new = kmem_cache_alloc(fasync_cache, GFP_KERNEL); if (!new) return -ENOMEM; spin_lock(&filp->f_lock); write_lock_irq(&fasync_lock); for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { if (fa->fa_file == filp) { if(on) { if (fa->fa_file != filp) continue; fa->fa_fd = fd; kmem_cache_free(fasync_cache, new); } else { *fp = fa->fa_next; kmem_cache_free(fasync_cache, fa); result = 1; } goto out; } } if (on) { new->magic = FASYNC_MAGIC; new->fa_file = filp; new->fa_fd = fd; new->fa_next = *fapp; *fapp = new; result = 1; } out: if (on) filp->f_flags |= FASYNC; else filp->f_flags &= ~FASYNC; out: write_unlock_irq(&fasync_lock); spin_unlock(&filp->f_lock); return result; } /* * fasync_helper() is used by almost all character device drivers * to set up the fasync queue, and for regular files by the file * lease code. It returns negative on error, 0 if it did no changes * and positive if it added/deleted the entry. */ int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) { if (!on) return fasync_remove_entry(filp, fapp); return fasync_add_entry(fd, filp, fapp); } EXPORT_SYMBOL(fasync_helper); void __kill_fasync(struct fasync_struct *fa, int sig, int band) Loading Loading
fs/fcntl.c +66 −36 Original line number Diff line number Diff line Loading @@ -618,60 +618,90 @@ static DEFINE_RWLOCK(fasync_lock); static struct kmem_cache *fasync_cache __read_mostly; /* * fasync_helper() is used by almost all character device drivers * to set up the fasync queue. It returns negative on error, 0 if it did * no changes and positive if it added/deleted the entry. * Remove a fasync entry. If successfully removed, return * positive and clear the FASYNC flag. If no entry exists, * do nothing and return 0. * * NOTE! It is very important that the FASYNC flag always * match the state "is the filp on a fasync list". * * We always take the 'filp->f_lock', in since fasync_lock * needs to be irq-safe. */ int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) static int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp) { struct fasync_struct *fa, **fp; struct fasync_struct *new = NULL; int result = 0; if (on) { new = kmem_cache_alloc(fasync_cache, GFP_KERNEL); if (!new) return -ENOMEM; spin_lock(&filp->f_lock); write_lock_irq(&fasync_lock); for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { if (fa->fa_file != filp) continue; *fp = fa->fa_next; kmem_cache_free(fasync_cache, fa); filp->f_flags &= ~FASYNC; result = 1; break; } write_unlock_irq(&fasync_lock); spin_unlock(&filp->f_lock); return result; } /* * We need to take f_lock first since it's not an IRQ-safe * lock. * Add a fasync entry. Return negative on error, positive if * added, and zero if did nothing but change an existing one. * * NOTE! It is very important that the FASYNC flag always * match the state "is the filp on a fasync list". */ static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp) { struct fasync_struct *new, *fa, **fp; int result = 0; new = kmem_cache_alloc(fasync_cache, GFP_KERNEL); if (!new) return -ENOMEM; spin_lock(&filp->f_lock); write_lock_irq(&fasync_lock); for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { if (fa->fa_file == filp) { if(on) { if (fa->fa_file != filp) continue; fa->fa_fd = fd; kmem_cache_free(fasync_cache, new); } else { *fp = fa->fa_next; kmem_cache_free(fasync_cache, fa); result = 1; } goto out; } } if (on) { new->magic = FASYNC_MAGIC; new->fa_file = filp; new->fa_fd = fd; new->fa_next = *fapp; *fapp = new; result = 1; } out: if (on) filp->f_flags |= FASYNC; else filp->f_flags &= ~FASYNC; out: write_unlock_irq(&fasync_lock); spin_unlock(&filp->f_lock); return result; } /* * fasync_helper() is used by almost all character device drivers * to set up the fasync queue, and for regular files by the file * lease code. It returns negative on error, 0 if it did no changes * and positive if it added/deleted the entry. */ int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) { if (!on) return fasync_remove_entry(filp, fapp); return fasync_add_entry(fd, filp, fapp); } EXPORT_SYMBOL(fasync_helper); void __kill_fasync(struct fasync_struct *fa, int sig, int band) Loading
