Revision b53df2e7442c73a932fb74228147fb946e531585 authored by Shin'ichiro Kawasaki on 21 February 2020, 01:37:08 UTC, committed by Jens Axboe on 12 March 2020, 13:54:39 UTC
Commit b72053072c0b ("block: allow partitions on host aware zone devices") introduced the helper function disk_has_partitions() to check if a given disk has valid partitions. However, since this function result directly depends on the disk partition table length rather than the actual existence of valid partitions in the table, it returns true even after all partitions are removed from the disk. For host aware zoned block devices, this results in zone management support to be kept disabled even after removing all partitions. Fix this by changing disk_has_partitions() to walk through the partition table entries and return true if and only if a valid non-zero size partition is found. Fixes: b72053072c0b ("block: allow partitions on host aware zone devices") Cc: stable@vger.kernel.org # 5.5 Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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mailbox.txt
============================
The Common Mailbox Framework
============================
:Author: Jassi Brar <jaswinder.singh@linaro.org>
This document aims to help developers write client and controller
drivers for the API. But before we start, let us note that the
client (especially) and controller drivers are likely going to be
very platform specific because the remote firmware is likely to be
proprietary and implement non-standard protocol. So even if two
platforms employ, say, PL320 controller, the client drivers can't
be shared across them. Even the PL320 driver might need to accommodate
some platform specific quirks. So the API is meant mainly to avoid
similar copies of code written for each platform. Having said that,
nothing prevents the remote f/w to also be Linux based and use the
same api there. However none of that helps us locally because we only
ever deal at client's protocol level.
Some of the choices made during implementation are the result of this
peculiarity of this "common" framework.
Controller Driver (See include/linux/mailbox_controller.h)
==========================================================
Allocate mbox_controller and the array of mbox_chan.
Populate mbox_chan_ops, except peek_data() all are mandatory.
The controller driver might know a message has been consumed
by the remote by getting an IRQ or polling some hardware flag
or it can never know (the client knows by way of the protocol).
The method in order of preference is IRQ -> Poll -> None, which
the controller driver should set via 'txdone_irq' or 'txdone_poll'
or neither.
Client Driver (See include/linux/mailbox_client.h)
==================================================
The client might want to operate in blocking mode (synchronously
send a message through before returning) or non-blocking/async mode (submit
a message and a callback function to the API and return immediately).
::
struct demo_client {
struct mbox_client cl;
struct mbox_chan *mbox;
struct completion c;
bool async;
/* ... */
};
/*
* This is the handler for data received from remote. The behaviour is purely
* dependent upon the protocol. This is just an example.
*/
static void message_from_remote(struct mbox_client *cl, void *mssg)
{
struct demo_client *dc = container_of(cl, struct demo_client, cl);
if (dc->async) {
if (is_an_ack(mssg)) {
/* An ACK to our last sample sent */
return; /* Or do something else here */
} else { /* A new message from remote */
queue_req(mssg);
}
} else {
/* Remote f/w sends only ACK packets on this channel */
return;
}
}
static void sample_sent(struct mbox_client *cl, void *mssg, int r)
{
struct demo_client *dc = container_of(cl, struct demo_client, cl);
complete(&dc->c);
}
static void client_demo(struct platform_device *pdev)
{
struct demo_client *dc_sync, *dc_async;
/* The controller already knows async_pkt and sync_pkt */
struct async_pkt ap;
struct sync_pkt sp;
dc_sync = kzalloc(sizeof(*dc_sync), GFP_KERNEL);
dc_async = kzalloc(sizeof(*dc_async), GFP_KERNEL);
/* Populate non-blocking mode client */
dc_async->cl.dev = &pdev->dev;
dc_async->cl.rx_callback = message_from_remote;
dc_async->cl.tx_done = sample_sent;
dc_async->cl.tx_block = false;
dc_async->cl.tx_tout = 0; /* doesn't matter here */
dc_async->cl.knows_txdone = false; /* depending upon protocol */
dc_async->async = true;
init_completion(&dc_async->c);
/* Populate blocking mode client */
dc_sync->cl.dev = &pdev->dev;
dc_sync->cl.rx_callback = message_from_remote;
dc_sync->cl.tx_done = NULL; /* operate in blocking mode */
dc_sync->cl.tx_block = true;
dc_sync->cl.tx_tout = 500; /* by half a second */
dc_sync->cl.knows_txdone = false; /* depending upon protocol */
dc_sync->async = false;
/* ASync mailbox is listed second in 'mboxes' property */
dc_async->mbox = mbox_request_channel(&dc_async->cl, 1);
/* Populate data packet */
/* ap.xxx = 123; etc */
/* Send async message to remote */
mbox_send_message(dc_async->mbox, &ap);
/* Sync mailbox is listed first in 'mboxes' property */
dc_sync->mbox = mbox_request_channel(&dc_sync->cl, 0);
/* Populate data packet */
/* sp.abc = 123; etc */
/* Send message to remote in blocking mode */
mbox_send_message(dc_sync->mbox, &sp);
/* At this point 'sp' has been sent */
/* Now wait for async chan to be done */
wait_for_completion(&dc_async->c);
}
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