linux-kernel - [PATCH v4 1/5] spi: spi-geni-qcom: No need for irqsave variant of spinlock calls

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 18 Jun 2020 08:06:22 -0700
From:   Douglas Anderson <dianders@...omium.org>
To:     Mark Brown <broonie@...nel.org>
Cc:     swboyd@...omium.org, Alok Chauhan <alokc@...eaurora.org>,
        skakit@...eaurora.org, Douglas Anderson <dianders@...omium.org>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-spi@...r.kernel.org
Subject: [PATCH v4 1/5] spi: spi-geni-qcom: No need for irqsave variant of spinlock calls

The driver locks its locks in two places.

In the first usage of the lock the function doing the locking already
has a sleeping call and thus we know we can't be called from interrupt
context.  That means we can use the "spin_lock_irq" variant of the
function.

In the second usage of the lock the function is the interrupt handler
and we know interrupt handlers are called with interrupts disabled.
That means we can use the "spin_lock" variant of the function.

This patch is expected to be a no-op and is just a cleanup / slight
optimization.

Signed-off-by: Douglas Anderson <dianders@...omium.org>
Reviewed-by: Stephen Boyd <swboyd@...omium.org>
---

Changes in v4: None
Changes in v3:
- ("spi: spi-geni-qcom: No need for irqsave variant...") new for v3

Changes in v2: None

 drivers/spi/spi-geni-qcom.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c
index c3972424af71..c7d2c7e45b3f 100644
--- a/drivers/spi/spi-geni-qcom.c
+++ b/drivers/spi/spi-geni-qcom.c
@@ -122,23 +122,23 @@ static void handle_fifo_timeout(struct spi_master *spi,
 				struct spi_message *msg)
 {
 	struct spi_geni_master *mas = spi_master_get_devdata(spi);
-	unsigned long time_left, flags;
+	unsigned long time_left;
 	struct geni_se *se = &mas->se;
 
-	spin_lock_irqsave(&mas->lock, flags);
+	spin_lock_irq(&mas->lock);
 	reinit_completion(&mas->xfer_done);
 	mas->cur_mcmd = CMD_CANCEL;
 	geni_se_cancel_m_cmd(se);
 	writel(0, se->base + SE_GENI_TX_WATERMARK_REG);
-	spin_unlock_irqrestore(&mas->lock, flags);
+	spin_unlock_irq(&mas->lock);
 	time_left = wait_for_completion_timeout(&mas->xfer_done, HZ);
 	if (time_left)
 		return;
 
-	spin_lock_irqsave(&mas->lock, flags);
+	spin_lock_irq(&mas->lock);
 	reinit_completion(&mas->xfer_done);
 	geni_se_abort_m_cmd(se);
-	spin_unlock_irqrestore(&mas->lock, flags);
+	spin_unlock_irq(&mas->lock);
 	time_left = wait_for_completion_timeout(&mas->xfer_done, HZ);
 	if (!time_left)
 		dev_err(mas->dev, "Failed to cancel/abort m_cmd\n");
@@ -477,12 +477,11 @@ static irqreturn_t geni_spi_isr(int irq, void *data)
 	struct spi_geni_master *mas = spi_master_get_devdata(spi);
 	struct geni_se *se = &mas->se;
 	u32 m_irq;
-	unsigned long flags;
 
 	if (mas->cur_mcmd == CMD_NONE)
 		return IRQ_NONE;
 
-	spin_lock_irqsave(&mas->lock, flags);
+	spin_lock(&mas->lock);
 	m_irq = readl(se->base + SE_GENI_M_IRQ_STATUS);
 
 	if ((m_irq & M_RX_FIFO_WATERMARK_EN) || (m_irq & M_RX_FIFO_LAST_EN))
@@ -524,7 +523,7 @@ static irqreturn_t geni_spi_isr(int irq, void *data)
 	}
 
 	writel(m_irq, se->base + SE_GENI_M_IRQ_CLEAR);
-	spin_unlock_irqrestore(&mas->lock, flags);
+	spin_unlock(&mas->lock);
 	return IRQ_HANDLED;
 }
 
-- 
2.27.0.290.gba653c62da-goog