Messages in this thread Patch in this message | | | From | Sean Nyekjaer <> | Subject | [PATCH 1/3] mtd: core: protect access to MTD devices while in suspend | Date | Mon, 11 Oct 2021 13:52:51 +0200 |
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Prevent accessing the devices 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.
Fixes: 013e6292aaf5 ("mtd: rawnand: Simplify the locking") Suggested-by: Boris Brezillon <boris.brezillon@collabora.com> Signed-off-by: Sean Nyekjaer <sean@geanix.com> --- drivers/mtd/mtdcore.c | 133 +++++++++++++++++++++++++++++++++++----- include/linux/mtd/mtd.h | 109 +++++++++++++++++++++++++++----- 2 files changed, 211 insertions(+), 31 deletions(-)
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index c8fd7f758938..51be9b46ef54 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) @@ -1257,6 +1259,8 @@ int mtd_erase(struct mtd_info *mtd, struct erase_info *instr) ledtrig_mtd_activity(); + mtd_start_access(mtd); + if (mtd->flags & MTD_SLC_ON_MLC_EMULATION) { adjinstr.addr = (loff_t)mtd_div_by_eb(instr->addr, mtd) * master->erasesize; @@ -1278,6 +1282,8 @@ int mtd_erase(struct mtd_info *mtd, struct erase_info *instr) } } + mtd_end_access(mtd); + return ret; } EXPORT_SYMBOL_GPL(mtd_erase); @@ -1289,6 +1295,7 @@ 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 +1308,12 @@ int mtd_point(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, if (!len) return 0; + mtd_start_access(mtd); 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(mtd); + + return ret; } EXPORT_SYMBOL_GPL(mtd_point); @@ -1310,6 +1321,7 @@ 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 +1329,12 @@ 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(mtd); + ret = master->_unpoint(master, mtd_get_master_ofs(mtd, from), len); + mtd_end_access(mtd); + + return ret; } EXPORT_SYMBOL_GPL(mtd_unpoint); @@ -1372,6 +1389,7 @@ int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, }; int ret; + /* mtd_read_oob handles mtd access protection */ ret = mtd_read_oob(mtd, from, &ops); *retlen = ops.retlen; @@ -1388,6 +1406,7 @@ int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, }; int ret; + /* mtd_write_oob handles mtd access protection */ ret = mtd_write_oob(mtd, to, &ops); *retlen = ops.retlen; @@ -1406,6 +1425,7 @@ int mtd_panic_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf) { struct mtd_info *master = mtd_get_master(mtd); + int ret; *retlen = 0; if (!master->_panic_write) @@ -1419,8 +1439,12 @@ int mtd_panic_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, if (!master->oops_panic_write) master->oops_panic_write = true; - return master->_panic_write(master, mtd_get_master_ofs(mtd, to), len, - retlen, buf); + mtd_start_access(mtd); + ret = master->_panic_write(master, mtd_get_master_ofs(mtd, to), len, + retlen, buf); + mtd_end_access(mtd); + + return ret; } EXPORT_SYMBOL_GPL(mtd_panic_write); @@ -1566,6 +1590,8 @@ int mtd_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops) ledtrig_mtd_activity(); + mtd_start_access(mtd); + /* Check the validity of a potential fallback on mtd->_read */ if (!master->_read_oob && (!master->_read || ops->oobbuf)) return -EOPNOTSUPP; @@ -1576,7 +1602,7 @@ int mtd_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops) ret_code = mtd_read_oob_std(mtd, from, ops); mtd_update_ecc_stats(mtd, master, &old_stats); - + mtd_end_access(mtd); /* * In cases where ops->datbuf != NULL, mtd->_read_oob() has semantics * similar to mtd->_read(), returning a non-negative integer @@ -1597,6 +1623,8 @@ int mtd_write_oob(struct mtd_info *mtd, loff_t to, struct mtd_info *master = mtd_get_master(mtd); int ret; + mtd_start_access(mtd); + ops->retlen = ops->oobretlen = 0; if (!(mtd->flags & MTD_WRITEABLE)) @@ -1615,7 +1643,10 @@ int mtd_write_oob(struct mtd_info *mtd, loff_t to, if (mtd->flags & MTD_SLC_ON_MLC_EMULATION) return mtd_io_emulated_slc(mtd, to, false, ops); - return mtd_write_oob_std(mtd, to, ops); + ret = mtd_write_oob_std(mtd, to, ops); + mtd_end_access(mtd); + + return ret; } EXPORT_SYMBOL_GPL(mtd_write_oob); @@ -1992,12 +2023,18 @@ 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(mtd); + ret = master->_get_fact_prot_info(master, len, retlen, buf); + mtd_end_access(mtd); + + return ret; } EXPORT_SYMBOL_GPL(mtd_get_fact_prot_info); @@ -2005,13 +2042,19 @@ 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(mtd); + ret = master->_read_fact_prot_reg(master, from, len, retlen, buf); + mtd_end_access(mtd); + + return ret; } EXPORT_SYMBOL_GPL(mtd_read_fact_prot_reg); @@ -2019,12 +2062,18 @@ 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(mtd); + ret = master->_get_user_prot_info(master, len, retlen, buf); + mtd_end_access(mtd); + + return ret; } EXPORT_SYMBOL_GPL(mtd_get_user_prot_info); @@ -2032,13 +2081,19 @@ 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(mtd); + ret = master->_read_user_prot_reg(master, from, len, retlen, buf); + mtd_end_access(mtd); + + return ret; } EXPORT_SYMBOL_GPL(mtd_read_user_prot_reg); @@ -2053,7 +2108,11 @@ 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(mtd); ret = master->_write_user_prot_reg(master, to, len, retlen, buf); + mtd_end_access(mtd); + if (ret) return ret; @@ -2068,24 +2127,36 @@ 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(mtd); + ret = master->_lock_user_prot_reg(master, from, len); + mtd_end_access(mtd); + + 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(mtd); + ret = master->_erase_user_prot_reg(master, from, len); + mtd_end_access(mtd); + + return ret; } EXPORT_SYMBOL_GPL(mtd_erase_user_prot_reg); @@ -2093,6 +2164,7 @@ 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 +2178,18 @@ 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(mtd); + ret = master->_lock(master, mtd_get_master_ofs(mtd, ofs), len); + mtd_end_access(mtd); + + 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 +2203,18 @@ 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(mtd); + ret = master->_unlock(master, mtd_get_master_ofs(mtd, ofs), len); + mtd_end_access(mtd); + + 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 +2228,18 @@ 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(mtd); + ret = master->_is_locked(master, mtd_get_master_ofs(mtd, ofs), len); + mtd_end_access(mtd); + + 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 +2249,18 @@ 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(mtd); + ret = master->_block_isreserved(master, mtd_get_master_ofs(mtd, ofs)); + mtd_end_access(mtd); + + 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 +2270,11 @@ 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(mtd); + ret = master->_block_isbad(master, mtd_get_master_ofs(mtd, ofs)); + mtd_end_access(mtd); + + return ret; } EXPORT_SYMBOL_GPL(mtd_block_isbad); @@ -2197,7 +2293,10 @@ 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(mtd); ret = master->_block_markbad(master, mtd_get_master_ofs(mtd, ofs)); + mtd_end_access(mtd); + if (ret) return ret; diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h index 88227044fc86..7765d1fcfc8b 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 +478,49 @@ 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 *mtd) +{ + struct mtd_info *master = mtd_get_master(mtd); + + /* + * 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 == 0); + } +} + +static inline void mtd_end_access(struct mtd_info *mtd) +{ + struct mtd_info *master = mtd_get_master(mtd); + + 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 +528,12 @@ 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(mtd); + ret = master->_max_bad_blocks(master, mtd_get_master_ofs(mtd, ofs), + len); + mtd_end_access(mtd); + + return ret; } int mtd_wunit_to_pairing_info(struct mtd_info *mtd, int wunit, @@ -543,33 +588,69 @@ int mtd_block_isreserved(struct mtd_info *mtd, loff_t ofs); int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs); 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 = 0; + + if (!master->_suspend) + return ret; + + if (!master->master.suspended) { + ret = master->_suspend(master); + if (!ret) + master->master.suspended = 1; + } + + return ret; +} + static inline int mtd_suspend(struct mtd_info *mtd) { struct mtd_info *master = mtd_get_master(mtd); - int ret; + int ret = 0; - if (master->master.suspended) - return 0; + if (!master->_suspend) + return ret; - ret = master->_suspend ? master->_suspend(master) : 0; - if (ret) + down_write(&master->master.suspend_lock); + ret = __mtd_suspend(mtd); + up_write(&master->master.suspend_lock); + + return ret; +} + +static inline int __mtd_resume(struct mtd_info *mtd) +{ + struct mtd_info *master = mtd_get_master(mtd); + int ret = 0; + + if (!master->_suspend) return ret; - master->master.suspended = 1; - return 0; + if (master->master.suspended) { + if (master->_resume) + master->_resume(master); + + master->master.suspended = 0; + ret = 1; + } + + 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); - - master->master.suspended = 0; + down_write(&master->master.suspend_lock); + /* If MTD dev has been resumed, wake up all waiters. */ + if (__mtd_resume(mtd)) + 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
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