linux-kernel - [PATCH 3/4] ide: don't disable interrupts during kmap

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Date:   Fri,  4 May 2018 16:24:45 +0200
From:   Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:     linux-ide@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, tglx@...utronix.de,
        "David S. Miller" <davem@...emloft.net>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: [PATCH 3/4] ide: don't disable interrupts during kmap_atomic()

ide_pio_bytes() disables interrupts around kmap_atomic(). This is a
leftover from the old kmap_atomic() implementation which relied on fixed
mapping slots, so the caller had to make sure that the same slot could not
be reused from an interrupting context.

kmap_atomic() was changed to dynamic slots long ago and commit 1ec9c5ddc17a
("include/linux/highmem.h: remove the second argument of k[un]map_atomic()")
removed the slot assignements, but the callers were not checked for now
redundant interrupt disabling.

Remove the conditional interrupt disable.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
 drivers/ide/ide-taskfile.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/drivers/ide/ide-taskfile.c b/drivers/ide/ide-taskfile.c
index abe0822dd429..49f9b4739779 100644
--- a/drivers/ide/ide-taskfile.c
+++ b/drivers/ide/ide-taskfile.c
@@ -237,7 +237,6 @@ void ide_pio_bytes(ide_drive_t *drive, struct ide_cmd *cmd,
 
 	while (len) {
 		unsigned nr_bytes = min(len, cursg->length - cmd->cursg_ofs);
-		int page_is_high;
 
 		page = sg_page(cursg);
 		offset = cursg->offset + cmd->cursg_ofs;
@@ -248,10 +247,6 @@ void ide_pio_bytes(ide_drive_t *drive, struct ide_cmd *cmd,
 
 		nr_bytes = min_t(unsigned, nr_bytes, (PAGE_SIZE - offset));
 
-		page_is_high = PageHighMem(page);
-		if (page_is_high)
-			local_irq_save(flags);
-
 		buf = kmap_atomic(page) + offset;
 
 		cmd->nleft -= nr_bytes;
@@ -270,9 +265,6 @@ void ide_pio_bytes(ide_drive_t *drive, struct ide_cmd *cmd,
 
 		kunmap_atomic(buf);
 
-		if (page_is_high)
-			local_irq_restore(flags);
-
 		len -= nr_bytes;
 	}
 }
-- 
2.17.0