On Wed, Sep 13, 2017 at 1:40 PM, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote: > Currently the host can be claimed by a task. Change this so that the host > can be claimed by a context that may or may not be a task. This provides > for the host to be claimed by a block driver queue to support blk-mq, while > maintaining compatibility with the existing use of mmc_claim_host(). > > Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx> I think this is a reasonable intermediate step as well. I am working to kill off the "big MMC host lock" by the following plan: DONE: - Convert all ioctl() ops to custom block layer requests (done) - Convert all debugfs ops to custom block layer requests (done) - Convert RPMB access to a character device to avoid one partition switch (just merged) REMAINS: - Convert boot and "general" partitions to be part of the main block device. Because they are. (This is really tricky and may require changes in the core kernel partition handling.) - Delete the dual mode card support. (No-one seems to be using it.) - Split the world in block access and SDIO with something like a simple mutex: either the host is a block device OR it is SDIO, and that state has the same lifetime as a card, since they are now either block devices or SDIO not both at the same time. - Implement a lighter lock for SDIO host claiming. - Now the lock should be gone... As you can see it is not entirely trivial :/ Linus
