kernel/git/stable/linux.git/drivers/mmc/card/block.c, branch master

mmc: block: Move files to core

2016-12-12T15:30:05+00:00

Once upon a time it made sense to keep the mmc block device driver and its related code, in its own directory called card. Over time, more an more functions/structures have become shared through generic mmc header files, between the core and the card directory. In other words, the relationship between them has become closer. By sharing functions/structures via generic header files, it becomes easy for outside users to abuse them. In a way to avoid that from happen, let's move the files from card directory into the core directory, as it enables us to move definitions of functions/structures into mmc core specific header files. Note, this is only the first step in providing a cleaner mmc interface for outside users. Following changes will do the actual cleanup, as that is not part of this change. Signed-off-by: Ulf Hansson Reviewed-by: Linus Walleij

mmc: queue: Fix queue thread wake-up

2016-12-05T09:31:03+00:00

The only time the driver sleeps expecting to be woken upon the arrival of a new request, is when the dispatch queue is empty. The only time that it is known whether the dispatch queue is empty is after NULL is returned from blk_fetch_request() while under the queue lock. Recognizing those facts, simplify the synchronization between the queue thread and the request function. A couple of flags tell the request function what to do, and the queue lock and barriers associated with wake-ups ensure synchronization. The result is simpler and allows the removal of the context_info lock. Signed-off-by: Adrian Hunter Reviewed-by: Linus Walleij Reviewed-by: Harjani Ritesh Signed-off-by: Ulf Hansson

mmc: block: Fix 4K native sector check

2016-12-05T09:31:03+00:00

The 4K native sector check does not allow for the 'do' loop nor the variables used after the 'cmd_abort' label. 'brq' and 'req' get reassigned in the 'do' loop, so the check must not assume what their values are. After the 'cmd_abort' label, 'mq_rq' and 'req' are used, but 'rqc' must be NULL otherwise it can be started again. Signed-off-by: Adrian Hunter Reviewed-by: Linus Walleij Signed-off-by: Ulf Hansson

mmc: block: Restore line inadvertently removed with packed commands

2016-12-05T09:30:34+00:00

Signed-off-by: Adrian Hunter Signed-off-by: Ulf Hansson Reviewed-by: Linus Walleij

mmc: block: delete packed command support

2016-11-29T08:05:27+00:00

I've had it with this code now. The packed command support is a complex hurdle in the MMC/SD block layer, around 500+ lines of code which was introduced in 2013 in commit ce39f9d17c14 ("mmc: support packed write command for eMMC4.5 devices") commit abd9ac144947 ("mmc: add packed command feature of eMMC4.5") ...and since then it has been rotting. The original author of the code has disappeared from the community and the mail address is bouncing. For the code to be exercised the host must flag that it supports packed commands, so in mmc_blk_prep_packed_list() which is called for every single request, the following construction appears: u8 max_packed_rw = 0; if ((rq_data_dir(cur) == WRITE) && mmc_host_packed_wr(card->host)) max_packed_rw = card->ext_csd.max_packed_writes; if (max_packed_rw == 0) goto no_packed; This has the following logical deductions: - Only WRITE commands can really be packed, so the solution is only half-done: we support packed WRITE but not packed READ. The packed command support has not been finalized by supporting reads in three years! - mmc_host_packed_wr() is just a static inline that checks host->caps2 & MMC_CAP2_PACKED_WR. The problem with this is that NO upstream host sets this capability flag! No driver in the kernel is using it, and we can't test it. Packed command may be supported in out-of-tree code, but I doubt it. I doubt that the code is even working anymore due to other refactorings in the MMC block layer, who would notice if patches affecting it broke packed commands? No one. - There is no Device Tree binding or code to mark a host as supporting packed read or write commands, just this flag in caps2, so for sure there are not any DT systems using it either. It has other problems as well: mmc_blk_prep_packed_list() is speculatively picking requests out of the request queue with blk_fetch_request() making the MMC/SD stack harder to convert to the multiqueue block layer. By this we get rid of an obstacle. The way I see it this is just cruft littering the MMC/SD stack. Cc: Namjae Jeon Cc: Maya Erez Acked-by: Jaehoon Chung Signed-off-by: Linus Walleij Signed-off-by: Ulf Hansson

mmc: block: move packed command struct init

2016-11-29T08:05:04+00:00

By moving the mmc_packed_init() and mmc_packed_clean() into the only file in the kernel where they are used, we save two exported functions and can staticize those to the block.c file. Signed-off-by: Linus Walleij Signed-off-by: Ulf Hansson

mmc: block: rename data to blkdata

2016-11-29T08:05:04+00:00

The struct mmc_blk_request contains an opaque void *data that is actually only used to store a pointer to a per-request struct mmc_blk_data. This is confusing, so rename the member to blkdata and forward-declare the block.c local struct. Signed-off-by: Linus Walleij Signed-off-by: Ulf Hansson

mmc: block: use mmc_req_is_special()

2016-11-29T08:05:03+00:00

Instead of open coding the check for the same thing that the helper checks: use the helper. Signed-off-by: Linus Walleij Signed-off-by: Ulf Hansson

mmc: core: use enum mmc_blk_status properly

2016-11-29T08:00:51+00:00

There were several instances of code using the enum mmc_blk_status by arbitrarily converting it to an int and throwing it around to different functions. This makes the code hard to understand to may give rise to strange errors. Especially the function prototype mmc_start_req() had to be modified to take a pointer to an enum mmc_blk_status and the function pointer .err_check() inside struct mmc_async_req needed to return an enum mmc_blk_status. In every case: instead of assigning the block layer error code to an int, use the enum, also change the signature of all functions actually passing this enum to use the enum. To make it possible to use the enum everywhere applicable, move it to so that all code actually using it can also see it. An interesting case was encountered in the MMC test code which did not return a enum mmc_blk_status at all in the .err_check function supposed to check whether asynchronous requests worked or not: instead it returned a normal -ERROR or even the test frameworks internal error codes. The test code would also pass on enum mmc_blk_status codes as error codes inside the test code instead of converting them to the local RESULT_* codes. I have tried to fix all instances properly and run some tests on the result. Cc: Chunyan Zhang Cc: Baolin Wang Signed-off-by: Linus Walleij Signed-off-by: Ulf Hansson

mmc: block: convert ecc_err to a bool

2016-11-29T08:00:50+00:00

The ecc_err flag is only assigned 0 or 1 and treated as a bool, so convert it to a bool. Cc: Chunyan Zhang Cc: Baolin Wang Signed-off-by: Linus Walleij Signed-off-by: Ulf Hansson