After checking all possible call chains to it821x_firmware_command here, my tool finds that it821x_firmware_command is never called in atomic context, namely never in an interrupt handler or holding a spinlock. And it821x_firmware_command calls kmalloc(GFP_KERNEL), so it proves again that it821x_firmware_command can call functions which can sleep. Thus mdelay can be replaced with usleep_range to avoid busy wait.
This is found by a static analysis tool named DCNS written by myself. Signed-off-by: Jia-Ju Bai <[email protected]> --- drivers/ata/pata_it821x.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/ata/pata_it821x.c b/drivers/ata/pata_it821x.c index 7a21edf..8468b30 100644 --- a/drivers/ata/pata_it821x.c +++ b/drivers/ata/pata_it821x.c @@ -683,7 +683,7 @@ static u8 *it821x_firmware_command(struct ata_port *ap, u8 cmd, int len) ioread16_rep(ap->ioaddr.data_addr, buf, len/2); return (u8 *)buf; } - mdelay(1); + usleep_range(500, 1000); } kfree(buf); printk(KERN_ERR "it821x_firmware_command: timeout\n"); -- 1.7.9.5
