linux-kernel - [PATCH v2 2/9] alpha: marvel: make use of raw

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Date:   Tue, 21 Mar 2017 17:43:02 -0500
From:   Julia Cartwright <julia@...com>
To:     Richard Henderson <rth@...ddle.net>,
        Ivan Kokshaysky <ink@...assic.park.msu.ru>,
        Matt Turner <mattst88@...il.com>
CC:     <linux-kernel@...r.kernel.org>, <linux-rt-users@...r.kernel.org>,
        <linux-alpha@...r.kernel.org>
Subject: [PATCH v2 2/9] alpha: marvel: make use of raw_spinlock variants

The alpha/marvel code currently implements an irq_chip for handling
interrupts; due to how irq_chip handling is done, it's necessary for the
irq_chip methods to be invoked from hardirq context, even on a a
real-time kernel.  Because the spinlock_t type becomes a "sleeping"
spinlock w/ RT kernels, it is not suitable to be used with irq_chips.

A quick audit of the operations under the lock reveal that they do only
minimal, bounded work, and are therefore safe to do under a raw spinlock.

Signed-off-by: Julia Cartwright <julia@...com>
---
v1 -> v2:
  - Add hunk which properly initializes the spin-lock (via kbuild bot).

 arch/alpha/include/asm/core_marvel.h |  2 +-
 arch/alpha/kernel/core_marvel.c      |  2 +-
 arch/alpha/kernel/sys_marvel.c       | 12 ++++++------
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/alpha/include/asm/core_marvel.h b/arch/alpha/include/asm/core_marvel.h
index dad300fa14ce..8dcf9dbda618 100644
--- a/arch/alpha/include/asm/core_marvel.h
+++ b/arch/alpha/include/asm/core_marvel.h
@@ -312,7 +312,7 @@ struct io7 {
 	io7_port7_csrs *csrs;
 	struct io7_port ports[IO7_NUM_PORTS];
 
-	spinlock_t irq_lock;
+	raw_spinlock_t irq_lock;
 };
 
 #ifndef __EXTERN_INLINE
diff --git a/arch/alpha/kernel/core_marvel.c b/arch/alpha/kernel/core_marvel.c
index d5f0580746a5..4300b1d1cf2c 100644
--- a/arch/alpha/kernel/core_marvel.c
+++ b/arch/alpha/kernel/core_marvel.c
@@ -118,7 +118,7 @@ alloc_io7(unsigned int pe)
 
 	io7 = alloc_bootmem(sizeof(*io7));
 	io7->pe = pe;
-	spin_lock_init(&io7->irq_lock);
+	raw_spin_lock_init(&io7->irq_lock);
 
 	for (h = 0; h < 4; h++) {
 		io7->ports[h].io7 = io7;
diff --git a/arch/alpha/kernel/sys_marvel.c b/arch/alpha/kernel/sys_marvel.c
index 24e41bd7d3c9..3e533920371f 100644
--- a/arch/alpha/kernel/sys_marvel.c
+++ b/arch/alpha/kernel/sys_marvel.c
@@ -115,11 +115,11 @@ io7_enable_irq(struct irq_data *d)
 		return;
 	}
 
-	spin_lock(&io7->irq_lock);
+	raw_spin_lock(&io7->irq_lock);
 	*ctl |= 1UL << 24;
 	mb();
 	*ctl;
-	spin_unlock(&io7->irq_lock);
+	raw_spin_unlock(&io7->irq_lock);
 }
 
 static void
@@ -136,11 +136,11 @@ io7_disable_irq(struct irq_data *d)
 		return;
 	}
 
-	spin_lock(&io7->irq_lock);
+	raw_spin_lock(&io7->irq_lock);
 	*ctl &= ~(1UL << 24);
 	mb();
 	*ctl;
-	spin_unlock(&io7->irq_lock);
+	raw_spin_unlock(&io7->irq_lock);
 }
 
 static void
@@ -263,7 +263,7 @@ init_io7_irqs(struct io7 *io7,
 	 */
 	printk("  Interrupts reported to CPU at PE %u\n", boot_cpuid);
 
-	spin_lock(&io7->irq_lock);
+	raw_spin_lock(&io7->irq_lock);
 
 	/* set up the error irqs */
 	io7_redirect_irq(io7, &io7->csrs->HLT_CTL.csr, boot_cpuid);
@@ -295,7 +295,7 @@ init_io7_irqs(struct io7 *io7,
 	for (i = 0; i < 16; ++i)
 		init_one_io7_msi(io7, i, boot_cpuid);
 
-	spin_unlock(&io7->irq_lock);
+	raw_spin_unlock(&io7->irq_lock);
 }
 
 static void __init
-- 
2.12.0