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| author | Pavel Skripkin <paskripkin@gmail.com> | 2022-07-06 16:28:45 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-07-07 18:05:36 -0700 |
| commit | f46fd3d7c3bd5d7bd5bb664135cf32ca9e97190b (patch) | |
| tree | 64d8562125d0d478f85ef4eab65e8f28ce8678cd /drivers | |
| parent | fe5235aef8558573c1d225199be3aaa7bcd22943 (diff) | |
| download | linux-stable-f46fd3d7c3bd5d7bd5bb664135cf32ca9e97190b.tar.gz linux-stable-f46fd3d7c3bd5d7bd5bb664135cf32ca9e97190b.tar.bz2 linux-stable-f46fd3d7c3bd5d7bd5bb664135cf32ca9e97190b.zip | |
net: ocelot: fix wrong time_after usage
Accidentally noticed, that this driver is the only user of
while (time_after(jiffies...)).
It looks like typo, because likely this while loop will finish after 1st
iteration, because time_after() returns true when 1st argument _is after_
2nd one.
There is one possible problem with this poll loop: the scheduler could put
the thread to sleep, and it does not get woken up for
OCELOT_FDMA_CH_SAFE_TIMEOUT_US. During that time, the hardware has done
its thing, but you exit the while loop and return -ETIMEDOUT.
Fix it by using sane poll API that avoids all problems described above
Fixes: 753a026cfec1 ("net: ocelot: add FDMA support")
Suggested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20220706132845.27968-1-paskripkin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/net/ethernet/mscc/ocelot_fdma.c | 17 |
1 files changed, 8 insertions, 9 deletions
diff --git a/drivers/net/ethernet/mscc/ocelot_fdma.c b/drivers/net/ethernet/mscc/ocelot_fdma.c index 083fddd263ec..8e3894cf5f7c 100644 --- a/drivers/net/ethernet/mscc/ocelot_fdma.c +++ b/drivers/net/ethernet/mscc/ocelot_fdma.c @@ -94,19 +94,18 @@ static void ocelot_fdma_activate_chan(struct ocelot *ocelot, dma_addr_t dma, ocelot_fdma_writel(ocelot, MSCC_FDMA_CH_ACTIVATE, BIT(chan)); } +static u32 ocelot_fdma_read_ch_safe(struct ocelot *ocelot) +{ + return ocelot_fdma_readl(ocelot, MSCC_FDMA_CH_SAFE); +} + static int ocelot_fdma_wait_chan_safe(struct ocelot *ocelot, int chan) { - unsigned long timeout; u32 safe; - timeout = jiffies + usecs_to_jiffies(OCELOT_FDMA_CH_SAFE_TIMEOUT_US); - do { - safe = ocelot_fdma_readl(ocelot, MSCC_FDMA_CH_SAFE); - if (safe & BIT(chan)) - return 0; - } while (time_after(jiffies, timeout)); - - return -ETIMEDOUT; + return readx_poll_timeout_atomic(ocelot_fdma_read_ch_safe, ocelot, safe, + safe & BIT(chan), 0, + OCELOT_FDMA_CH_SAFE_TIMEOUT_US); } static void ocelot_fdma_dcb_set_data(struct ocelot_fdma_dcb *dcb, |