Messages in this thread Patch in this message | | | From | Sean Nyekjaer <> | Subject | [PATCH v5 3/4] mtd: core: protect access to MTD devices while in suspend | Date | Tue, 2 Nov 2021 12:02:03 +0100 |
| |
Prevent MTD access while in a suspended state. Also prevent suspending a device which is still currently in use.
Commit 013e6292aaf5 ("mtd: rawnand: Simplify the locking") allows the rawnand layer to return errors rather than waiting in a blocking wait.
Tested on a iMX6ULL.
Suggested-by: Boris Brezillon <boris.brezillon@collabora.com> Signed-off-by: Sean Nyekjaer <sean@geanix.com> --- drivers/mtd/mtdcore.c | 115 +++++++++++++++++++++++++++++++++++----- include/linux/mtd/mtd.h | 81 +++++++++++++++++++++++----- 2 files changed, 169 insertions(+), 27 deletions(-)
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index 153229198947..f02b602b3fa9 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -777,6 +777,8 @@ static void mtd_set_dev_defaults(struct mtd_info *mtd) INIT_LIST_HEAD(&mtd->partitions); mutex_init(&mtd->master.partitions_lock); mutex_init(&mtd->master.chrdev_lock); + init_waitqueue_head(&mtd->master.resume_wq); + init_rwsem(&mtd->master.suspend_lock); } static ssize_t mtd_otp_size(struct mtd_info *mtd, bool is_user) @@ -1267,7 +1269,9 @@ int mtd_erase(struct mtd_info *mtd, struct erase_info *instr) adjinstr.addr += mst_ofs; + mtd_start_access(master); ret = master->_erase(master, &adjinstr); + mtd_end_access(master); if (adjinstr.fail_addr != MTD_FAIL_ADDR_UNKNOWN) { instr->fail_addr = adjinstr.fail_addr - mst_ofs; @@ -1289,6 +1293,7 @@ int mtd_point(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, void **virt, resource_size_t *phys) { struct mtd_info *master = mtd_get_master(mtd); + int ret; *retlen = 0; *virt = NULL; @@ -1301,8 +1306,12 @@ int mtd_point(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, if (!len) return 0; + mtd_start_access(master); from = mtd_get_master_ofs(mtd, from); - return master->_point(master, from, len, retlen, virt, phys); + ret = master->_point(master, from, len, retlen, virt, phys); + mtd_end_access(master); + + return ret; } EXPORT_SYMBOL_GPL(mtd_point); @@ -1310,6 +1319,7 @@ EXPORT_SYMBOL_GPL(mtd_point); int mtd_unpoint(struct mtd_info *mtd, loff_t from, size_t len) { struct mtd_info *master = mtd_get_master(mtd); + int ret; if (!master->_unpoint) return -EOPNOTSUPP; @@ -1317,7 +1327,12 @@ int mtd_unpoint(struct mtd_info *mtd, loff_t from, size_t len) return -EINVAL; if (!len) return 0; - return master->_unpoint(master, mtd_get_master_ofs(mtd, from), len); + + mtd_start_access(master); + ret = master->_unpoint(master, mtd_get_master_ofs(mtd, from), len); + mtd_end_access(master); + + return ret; } EXPORT_SYMBOL_GPL(mtd_unpoint); @@ -1372,6 +1387,7 @@ int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, }; int ret; + /* mtd_read_oob_std handles mtd access protection */ ret = mtd_read_oob(mtd, from, &ops); *retlen = ops.retlen; @@ -1388,6 +1404,7 @@ int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, }; int ret; + /* mtd_write_oob_std handles mtd access protection */ ret = mtd_write_oob(mtd, to, &ops); *retlen = ops.retlen; @@ -1464,11 +1481,13 @@ static int mtd_read_oob_std(struct mtd_info *mtd, loff_t from, int ret; from = mtd_get_master_ofs(mtd, from); + mtd_start_access(master); if (master->_read_oob) ret = master->_read_oob(master, from, ops); else ret = master->_read(master, from, ops->len, &ops->retlen, ops->datbuf); + mtd_end_access(master); return ret; } @@ -1480,11 +1499,13 @@ static int mtd_write_oob_std(struct mtd_info *mtd, loff_t to, int ret; to = mtd_get_master_ofs(mtd, to); + mtd_start_access(master); if (master->_write_oob) ret = master->_write_oob(master, to, ops); else ret = master->_write(master, to, ops->len, &ops->retlen, ops->datbuf); + mtd_end_access(master); return ret; } @@ -1992,12 +2013,18 @@ int mtd_get_fact_prot_info(struct mtd_info *mtd, size_t len, size_t *retlen, struct otp_info *buf) { struct mtd_info *master = mtd_get_master(mtd); + int ret; if (!master->_get_fact_prot_info) return -EOPNOTSUPP; if (!len) return 0; - return master->_get_fact_prot_info(master, len, retlen, buf); + + mtd_start_access(master); + ret = master->_get_fact_prot_info(master, len, retlen, buf); + mtd_end_access(master); + + return ret; } EXPORT_SYMBOL_GPL(mtd_get_fact_prot_info); @@ -2005,13 +2032,19 @@ int mtd_read_fact_prot_reg(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf) { struct mtd_info *master = mtd_get_master(mtd); + int ret; *retlen = 0; if (!master->_read_fact_prot_reg) return -EOPNOTSUPP; if (!len) return 0; - return master->_read_fact_prot_reg(master, from, len, retlen, buf); + + mtd_start_access(master); + ret = master->_read_fact_prot_reg(master, from, len, retlen, buf); + mtd_end_access(master); + + return ret; } EXPORT_SYMBOL_GPL(mtd_read_fact_prot_reg); @@ -2019,12 +2052,18 @@ int mtd_get_user_prot_info(struct mtd_info *mtd, size_t len, size_t *retlen, struct otp_info *buf) { struct mtd_info *master = mtd_get_master(mtd); + int ret; if (!master->_get_user_prot_info) return -EOPNOTSUPP; if (!len) return 0; - return master->_get_user_prot_info(master, len, retlen, buf); + + mtd_start_access(master); + ret = master->_get_user_prot_info(master, len, retlen, buf); + mtd_end_access(master); + + return ret; } EXPORT_SYMBOL_GPL(mtd_get_user_prot_info); @@ -2032,13 +2071,19 @@ int mtd_read_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf) { struct mtd_info *master = mtd_get_master(mtd); + int ret; *retlen = 0; if (!master->_read_user_prot_reg) return -EOPNOTSUPP; if (!len) return 0; - return master->_read_user_prot_reg(master, from, len, retlen, buf); + + mtd_start_access(master); + ret = master->_read_user_prot_reg(master, from, len, retlen, buf); + mtd_end_access(master); + + return ret; } EXPORT_SYMBOL_GPL(mtd_read_user_prot_reg); @@ -2053,7 +2098,11 @@ int mtd_write_user_prot_reg(struct mtd_info *mtd, loff_t to, size_t len, return -EOPNOTSUPP; if (!len) return 0; + + mtd_start_access(master); ret = master->_write_user_prot_reg(master, to, len, retlen, buf); + mtd_end_access(master); + if (ret) return ret; @@ -2068,24 +2117,36 @@ EXPORT_SYMBOL_GPL(mtd_write_user_prot_reg); int mtd_lock_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len) { struct mtd_info *master = mtd_get_master(mtd); + int ret; if (!master->_lock_user_prot_reg) return -EOPNOTSUPP; if (!len) return 0; - return master->_lock_user_prot_reg(master, from, len); + + mtd_start_access(master); + ret = master->_lock_user_prot_reg(master, from, len); + mtd_end_access(master); + + return ret; } EXPORT_SYMBOL_GPL(mtd_lock_user_prot_reg); int mtd_erase_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len) { struct mtd_info *master = mtd_get_master(mtd); + int ret; if (!master->_erase_user_prot_reg) return -EOPNOTSUPP; if (!len) return 0; - return master->_erase_user_prot_reg(master, from, len); + + mtd_start_access(master); + ret = master->_erase_user_prot_reg(master, from, len); + mtd_end_access(master); + + return ret; } EXPORT_SYMBOL_GPL(mtd_erase_user_prot_reg); @@ -2093,6 +2154,7 @@ EXPORT_SYMBOL_GPL(mtd_erase_user_prot_reg); int mtd_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len) { struct mtd_info *master = mtd_get_master(mtd); + int ret; if (!master->_lock) return -EOPNOTSUPP; @@ -2106,13 +2168,18 @@ int mtd_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len) len = (u64)mtd_div_by_eb(len, mtd) * master->erasesize; } - return master->_lock(master, mtd_get_master_ofs(mtd, ofs), len); + mtd_start_access(master); + ret = master->_lock(master, mtd_get_master_ofs(mtd, ofs), len); + mtd_end_access(master); + + return ret; } EXPORT_SYMBOL_GPL(mtd_lock); int mtd_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len) { struct mtd_info *master = mtd_get_master(mtd); + int ret; if (!master->_unlock) return -EOPNOTSUPP; @@ -2126,13 +2193,18 @@ int mtd_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len) len = (u64)mtd_div_by_eb(len, mtd) * master->erasesize; } - return master->_unlock(master, mtd_get_master_ofs(mtd, ofs), len); + mtd_start_access(master); + ret = master->_unlock(master, mtd_get_master_ofs(mtd, ofs), len); + mtd_end_access(master); + + return ret; } EXPORT_SYMBOL_GPL(mtd_unlock); int mtd_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len) { struct mtd_info *master = mtd_get_master(mtd); + int ret; if (!master->_is_locked) return -EOPNOTSUPP; @@ -2146,13 +2218,18 @@ int mtd_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len) len = (u64)mtd_div_by_eb(len, mtd) * master->erasesize; } - return master->_is_locked(master, mtd_get_master_ofs(mtd, ofs), len); + mtd_start_access(master); + ret = master->_is_locked(master, mtd_get_master_ofs(mtd, ofs), len); + mtd_end_access(master); + + return ret; } EXPORT_SYMBOL_GPL(mtd_is_locked); int mtd_block_isreserved(struct mtd_info *mtd, loff_t ofs) { struct mtd_info *master = mtd_get_master(mtd); + int ret; if (ofs < 0 || ofs >= mtd->size) return -EINVAL; @@ -2162,13 +2239,18 @@ int mtd_block_isreserved(struct mtd_info *mtd, loff_t ofs) if (mtd->flags & MTD_SLC_ON_MLC_EMULATION) ofs = (loff_t)mtd_div_by_eb(ofs, mtd) * master->erasesize; - return master->_block_isreserved(master, mtd_get_master_ofs(mtd, ofs)); + mtd_start_access(master); + ret = master->_block_isreserved(master, mtd_get_master_ofs(mtd, ofs)); + mtd_end_access(master); + + return ret; } EXPORT_SYMBOL_GPL(mtd_block_isreserved); int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs) { struct mtd_info *master = mtd_get_master(mtd); + int ret; if (ofs < 0 || ofs >= mtd->size) return -EINVAL; @@ -2178,7 +2260,11 @@ int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs) if (mtd->flags & MTD_SLC_ON_MLC_EMULATION) ofs = (loff_t)mtd_div_by_eb(ofs, mtd) * master->erasesize; - return master->_block_isbad(master, mtd_get_master_ofs(mtd, ofs)); + mtd_start_access(master); + ret = master->_block_isbad(master, mtd_get_master_ofs(mtd, ofs)); + mtd_end_access(master); + + return ret; } EXPORT_SYMBOL_GPL(mtd_block_isbad); @@ -2197,7 +2283,10 @@ int mtd_block_markbad(struct mtd_info *mtd, loff_t ofs) if (mtd->flags & MTD_SLC_ON_MLC_EMULATION) ofs = (loff_t)mtd_div_by_eb(ofs, mtd) * master->erasesize; + mtd_start_access(master); ret = master->_block_markbad(master, mtd_get_master_ofs(mtd, ofs)); + mtd_end_access(master); + if (ret) return ret; diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h index 88227044fc86..b074106e2d8e 100644 --- a/include/linux/mtd/mtd.h +++ b/include/linux/mtd/mtd.h @@ -231,6 +231,8 @@ struct mtd_master { struct mutex partitions_lock; struct mutex chrdev_lock; unsigned int suspended : 1; + wait_queue_head_t resume_wq; + struct rw_semaphore suspend_lock; }; struct mtd_info { @@ -476,10 +478,47 @@ static inline u32 mtd_oobavail(struct mtd_info *mtd, struct mtd_oob_ops *ops) return ops->mode == MTD_OPS_AUTO_OOB ? mtd->oobavail : mtd->oobsize; } +static inline void mtd_start_access(struct mtd_info *master) +{ + WARN_ON_ONCE(master != mtd_get_master(master)); + + /* + * Don't take the suspend_lock on devices that don't + * implement the suspend hook. Otherwise, lockdep will + * complain about nested locks when trying to suspend MTD + * partitions or MTD devices created by gluebi which are + * backed by real devices. + */ + if (!master->_suspend) + return; + + /* + * Wait until the device is resumed. Should we have a + * non-blocking mode here? + */ + while (1) { + down_read(&master->master.suspend_lock); + if (!master->master.suspended) + return; + + up_read(&master->master.suspend_lock); + wait_event(master->master.resume_wq, !master->master.suspended); + } +} + +static inline void mtd_end_access(struct mtd_info *master) +{ + if (!master->_suspend) + return; + + up_read(&master->master.suspend_lock); +} + static inline int mtd_max_bad_blocks(struct mtd_info *mtd, loff_t ofs, size_t len) { struct mtd_info *master = mtd_get_master(mtd); + int ret; if (!master->_max_bad_blocks) return -ENOTSUPP; @@ -487,8 +526,12 @@ static inline int mtd_max_bad_blocks(struct mtd_info *mtd, if (mtd->size < (len + ofs) || ofs < 0) return -EINVAL; - return master->_max_bad_blocks(master, mtd_get_master_ofs(mtd, ofs), - len); + mtd_start_access(master); + ret = master->_max_bad_blocks(master, mtd_get_master_ofs(mtd, ofs), + len); + mtd_end_access(master); + + return ret; } int mtd_wunit_to_pairing_info(struct mtd_info *mtd, int wunit, @@ -546,30 +589,40 @@ int mtd_block_markbad(struct mtd_info *mtd, loff_t ofs); static inline int mtd_suspend(struct mtd_info *mtd) { struct mtd_info *master = mtd_get_master(mtd); - int ret; - - if (master->master.suspended) - return 0; + int ret = 0; - ret = master->_suspend ? master->_suspend(master) : 0; - if (ret) + if (!master->_suspend) return ret; - master->master.suspended = 1; - return 0; + down_write(&master->master.suspend_lock); + if (!master->master.suspended) { + ret = master->_suspend(master); + if (!ret) + master->master.suspended = 1; + } + up_write(&master->master.suspend_lock); + + return ret; } static inline void mtd_resume(struct mtd_info *mtd) { struct mtd_info *master = mtd_get_master(mtd); - if (!master->master.suspended) + if (!master->_suspend) return; - if (master->_resume) - master->_resume(master); + down_write(&master->master.suspend_lock); + if (master->master.suspended) { + if (master->_resume) + master->_resume(master); + + master->master.suspended = 0; - master->master.suspended = 0; + /* The MTD dev has been resumed, wake up all waiters. */ + wake_up_all(&master->master.resume_wq); + } + up_write(&master->master.suspend_lock); } static inline uint32_t mtd_div_by_eb(uint64_t sz, struct mtd_info *mtd) -- 2.33.0
| |