From 1398788fe7b730db10e97dcb9f838603e41922d5 Mon Sep 17 00:00:00 2001 From: Artem Bityutskiy Date: Mon, 29 Jun 2009 15:58:36 +0300 Subject: [PATCH] UBI: remove bogus debugging checks The 'paranoid_check_empty()' is bogus because, which is easilly seen on NOR flash, which has long erase cycles, and which may easilly end-up with half-erased eraseblocks. In this case the paranoid check fails. I is just wrong to assume that PEBs which do not have EC headers always contain all 0xFF. Such assumption should not be made on the I/O level, which is quite low. Thus, just kill the check. Signed-off-by: Artem Bityutskiy --- drivers/mtd/ubi/debug.h | 1 + drivers/mtd/ubi/io.c | 87 ----------------------------------------- drivers/mtd/ubi/wl.c | 2 +- 3 files changed, 2 insertions(+), 88 deletions(-) diff --git a/drivers/mtd/ubi/debug.h b/drivers/mtd/ubi/debug.h index 6fc7fda2ab91..a4da7a09b949 100644 --- a/drivers/mtd/ubi/debug.h +++ b/drivers/mtd/ubi/debug.h @@ -173,6 +173,7 @@ static inline int ubi_dbg_is_erase_failure(void) #define ubi_dbg_is_bitflip() 0 #define ubi_dbg_is_write_failure() 0 #define ubi_dbg_is_erase_failure() 0 +#define ubi_dbg_check_all_ff(ubi, pnum, offset, len) 0 #endif /* !CONFIG_MTD_UBI_DEBUG */ #endif /* !__UBI_DEBUG_H__ */ diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c index 6c5441e8791d..c8edbfd09b64 100644 --- a/drivers/mtd/ubi/io.c +++ b/drivers/mtd/ubi/io.c @@ -98,14 +98,12 @@ static int paranoid_check_ec_hdr(const struct ubi_device *ubi, int pnum, static int paranoid_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum); static int paranoid_check_vid_hdr(const struct ubi_device *ubi, int pnum, const struct ubi_vid_hdr *vid_hdr); -static int paranoid_check_empty(struct ubi_device *ubi, int pnum); #else #define paranoid_check_not_bad(ubi, pnum) 0 #define paranoid_check_peb_ec_hdr(ubi, pnum) 0 #define paranoid_check_ec_hdr(ubi, pnum, ec_hdr) 0 #define paranoid_check_peb_vid_hdr(ubi, pnum) 0 #define paranoid_check_vid_hdr(ubi, pnum, vid_hdr) 0 -#define paranoid_check_empty(ubi, pnum) 0 #endif /** @@ -669,10 +667,6 @@ int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum, if (read_err != -EBADMSG && check_pattern(ec_hdr, 0xFF, UBI_EC_HDR_SIZE)) { /* The physical eraseblock is supposedly empty */ - err = ubi_dbg_check_all_ff(ubi, pnum, 0, ubi->peb_size); - if (err) - return err > 0 ? UBI_IO_BAD_EC_HDR : err; - if (verbose) ubi_warn("no EC header found at PEB %d, " "only 0xFF bytes", pnum); @@ -943,15 +937,6 @@ int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum, if (read_err != -EBADMSG && check_pattern(vid_hdr, 0xFF, UBI_VID_HDR_SIZE)) { /* The physical eraseblock is supposedly free */ - - /* - * The below is just a paranoid check, it has to be - * compiled out if paranoid checks are disabled. - */ - err = paranoid_check_empty(ubi, pnum); - if (err) - return err > 0 ? UBI_IO_BAD_VID_HDR : err; - if (verbose) ubi_warn("no VID header found at PEB %d, " "only 0xFF bytes", pnum); @@ -1241,8 +1226,6 @@ int ubi_dbg_check_all_ff(struct ubi_device *ubi, int pnum, int offset, int len) int err; loff_t addr = (loff_t)pnum * ubi->peb_size + offset; - ubi_assert(!mutex_is_locked(&ubi->dbg_buf_mutex)); - mutex_lock(&ubi->dbg_buf_mutex); err = ubi->mtd->read(ubi->mtd, addr, len, &read, ubi->dbg_peb_buf); if (err && err != -EUCLEAN) { @@ -1273,74 +1256,4 @@ error: return err; } -/** - * paranoid_check_empty - whether a PEB is empty. - * @ubi: UBI device description object - * @pnum: the physical eraseblock number to check - * - * This function makes sure PEB @pnum is empty, which means it contains only - * %0xFF data bytes. Returns zero if the PEB is empty, %1 if not, and a - * negative error code in case of failure. - * - * Empty PEBs have the EC header, and do not have the VID header. The caller of - * this function should have already made sure the PEB does not have the VID - * header. However, this function re-checks that, because it is possible that - * the header and data has already been written to the PEB. - * - * Let's consider a possible scenario. Suppose there are 2 tasks - A and B. - * Task A is in 'wear_leveling_worker()'. It is reading VID header of PEB X to - * find which LEB it corresponds to. PEB X is currently unmapped, and has no - * VID header. Task B is trying to write to PEB X. - * - * Task A: in 'ubi_io_read_vid_hdr()': reads the VID header from PEB X. The - * read data contain all 0xFF bytes; - * Task B: writes VID header and some data to PEB X; - * Task A: assumes PEB X is empty, calls 'paranoid_check_empty()'. And if we - * do not re-read the VID header, and do not cancel the checking if it - * is there, we fail. - */ -static int paranoid_check_empty(struct ubi_device *ubi, int pnum) -{ - int err, offs = ubi->vid_hdr_aloffset, len = ubi->vid_hdr_alsize; - size_t read; - uint32_t magic; - const struct ubi_vid_hdr *vid_hdr; - - mutex_lock(&ubi->dbg_buf_mutex); - err = ubi->mtd->read(ubi->mtd, offs, len, &read, ubi->dbg_peb_buf); - if (err && err != -EUCLEAN) { - ubi_err("error %d while reading %d bytes from PEB %d:%d, " - "read %zd bytes", err, len, pnum, offs, read); - goto error; - } - - vid_hdr = ubi->dbg_peb_buf; - magic = be32_to_cpu(vid_hdr->magic); - if (magic == UBI_VID_HDR_MAGIC) - /* The PEB contains VID header, so it is not empty */ - goto out; - - err = check_pattern(ubi->dbg_peb_buf, 0xFF, len); - if (err == 0) { - ubi_err("flash region at PEB %d:%d, length %d does not " - "contain all 0xFF bytes", pnum, offs, len); - goto fail; - } - -out: - mutex_unlock(&ubi->dbg_buf_mutex); - return 0; - -fail: - ubi_err("paranoid check failed for PEB %d", pnum); - ubi_msg("hex dump of the %d-%d region", offs, offs + len); - print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1, - ubi->dbg_peb_buf, len, 1); - err = 1; -error: - ubi_dbg_dump_stack(); - mutex_unlock(&ubi->dbg_buf_mutex); - return err; -} - #endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */ diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c index e4be446e05ed..600c7229d5cf 100644 --- a/drivers/mtd/ubi/wl.c +++ b/drivers/mtd/ubi/wl.c @@ -463,7 +463,7 @@ retry: err = ubi_dbg_check_all_ff(ubi, e->pnum, ubi->vid_hdr_aloffset, ubi->peb_size - ubi->vid_hdr_aloffset); if (err) { - dbg_err("new PEB does not contain all 0xFF bytes"); + ubi_err("new PEB %d does not contain all 0xFF bytes", e->pnum); return err > 0 ? -EINVAL : err; } -- 2.39.5