From 7684bd334d9d4ca4f09873e88d9c0131a2cf6c3b Mon Sep 17 00:00:00 2001 From: Peng Wang Date: Tue, 30 Oct 2018 15:52:34 +0800 Subject: pstore: Avoid duplicate call of persistent_ram_zap() When initialing a prz, if invalid data is found (no PERSISTENT_RAM_SIG), the function call path looks like this: ramoops_init_prz -> persistent_ram_new -> persistent_ram_post_init -> persistent_ram_zap persistent_ram_zap As we can see, persistent_ram_zap() is called twice. We can avoid this by adding an option to persistent_ram_new(), and only call persistent_ram_zap() when it is needed. Signed-off-by: Peng Wang [kees: minor tweak to exit path and commit log] Signed-off-by: Kees Cook --- fs/pstore/ram_core.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) (limited to 'fs/pstore/ram_core.c') diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c index 12e21f789194..23ca6f2c98a0 100644 --- a/fs/pstore/ram_core.c +++ b/fs/pstore/ram_core.c @@ -489,6 +489,7 @@ static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig, struct persistent_ram_ecc_info *ecc_info) { int ret; + bool zap = !!(prz->flags & PRZ_FLAG_ZAP_OLD); ret = persistent_ram_init_ecc(prz, ecc_info); if (ret) @@ -498,23 +499,25 @@ static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig, if (prz->buffer->sig == sig) { if (buffer_size(prz) > prz->buffer_size || - buffer_start(prz) > buffer_size(prz)) + buffer_start(prz) > buffer_size(prz)) { pr_info("found existing invalid buffer, size %zu, start %zu\n", buffer_size(prz), buffer_start(prz)); - else { + zap = true; + } else { pr_debug("found existing buffer, size %zu, start %zu\n", buffer_size(prz), buffer_start(prz)); persistent_ram_save_old(prz); - return 0; } } else { pr_debug("no valid data in buffer (sig = 0x%08x)\n", prz->buffer->sig); + prz->buffer->sig = sig; + zap = true; } - /* Rewind missing or invalid memory area. */ - prz->buffer->sig = sig; - persistent_ram_zap(prz); + /* Reset missing, invalid, or single-use memory area. */ + if (zap) + persistent_ram_zap(prz); return 0; } -- cgit v1.2.3-58-ga151