Commit eada8598 authored Jan 25, 2018 by Jia-Ju Bai Committed by Tejun Heo Jan 25, 2018

ata: pata_it821x: Replace mdelay with usleep_range in it821x_firmware_command



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 <baijiaju1990@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

parent e72685db

drivers/ata/pata_it821x.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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");