From 8d127504d0b4d9a909add9b235f36d40b3ce7f6a Mon Sep 17 00:00:00 2001 From: Zhang Mingli Date: Thu, 12 Jan 2023 14:11:43 +0800 Subject: [PATCH v0] Fix condition in shm_toc and remove unused function shm_toc_freespace. Fix bogus condition in shm_toc_insert and shm_toc_allocate. Take a sizeof(shm_entry) into account when shm_toc_allocate. Remove unused function shm_toc_freespace. --- src/backend/storage/ipc/shm_toc.c | 26 +------------------------- src/include/storage/shm_toc.h | 1 - 2 files changed, 1 insertion(+), 26 deletions(-) diff --git a/src/backend/storage/ipc/shm_toc.c b/src/backend/storage/ipc/shm_toc.c index 0cd824400f..37bd0dd25f 100644 --- a/src/backend/storage/ipc/shm_toc.c +++ b/src/backend/storage/ipc/shm_toc.c @@ -110,7 +110,7 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) + allocated_bytes; /* Check for memory exhaustion and overflow. */ - if (toc_bytes + nbytes > total_bytes || toc_bytes + nbytes < toc_bytes) + if (toc_bytes + sizeof(shm_toc_entry) + nbytes > total_bytes) { SpinLockRelease(&toc->toc_mutex); ereport(ERROR, @@ -124,29 +124,6 @@ shm_toc_allocate(shm_toc *toc, Size nbytes) return ((char *) toc) + (total_bytes - allocated_bytes - nbytes); } -/* - * Return the number of bytes that can still be allocated. - */ -Size -shm_toc_freespace(shm_toc *toc) -{ - volatile shm_toc *vtoc = toc; - Size total_bytes; - Size allocated_bytes; - Size nentry; - Size toc_bytes; - - SpinLockAcquire(&toc->toc_mutex); - total_bytes = vtoc->toc_total_bytes; - allocated_bytes = vtoc->toc_allocated_bytes; - nentry = vtoc->toc_nentry; - SpinLockRelease(&toc->toc_mutex); - - toc_bytes = offsetof(shm_toc, toc_entry) + nentry * sizeof(shm_toc_entry); - Assert(allocated_bytes + BUFFERALIGN(toc_bytes) <= total_bytes); - return total_bytes - (allocated_bytes + BUFFERALIGN(toc_bytes)); -} - /* * Insert a TOC entry. * @@ -191,7 +168,6 @@ shm_toc_insert(shm_toc *toc, uint64 key, void *address) /* Check for memory exhaustion and overflow. */ if (toc_bytes + sizeof(shm_toc_entry) > total_bytes || - toc_bytes + sizeof(shm_toc_entry) < toc_bytes || nentry >= PG_UINT32_MAX) { SpinLockRelease(&toc->toc_mutex); diff --git a/src/include/storage/shm_toc.h b/src/include/storage/shm_toc.h index 7a2f8e9934..5f2abcc613 100644 --- a/src/include/storage/shm_toc.h +++ b/src/include/storage/shm_toc.h @@ -30,7 +30,6 @@ typedef struct shm_toc shm_toc; extern shm_toc *shm_toc_create(uint64 magic, void *address, Size nbytes); extern shm_toc *shm_toc_attach(uint64 magic, void *address); extern void *shm_toc_allocate(shm_toc *toc, Size nbytes); -extern Size shm_toc_freespace(shm_toc *toc); extern void shm_toc_insert(shm_toc *toc, uint64 key, void *address); extern void *shm_toc_lookup(shm_toc *toc, uint64 key, bool noError); -- 2.34.1