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Rao" , Yury Norov , linuxppc-dev@lists.ozlabs.org Subject: [PATCH v4 40/40] powerpc/xive: drop locking around IRQ map Date: Thu, 20 Jun 2024 10:57:03 -0700 Message-ID: <20240620175703.605111-41-yury.norov@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240620175703.605111-1-yury.norov@gmail.com> References: <20240620175703.605111-1-yury.norov@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sergey Shtylyov , Jan Kara , Bart Van Assche , Rasmus Villemoes , Matthew Wilcox , Alexey Klimov , Linus Torvalds , Mirsad Todorovac Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" The code operates on individual bits of the bitmap, and leveraging atomic find ops we can drop locking scheme around the map. Signed-off-by: Yury Norov --- arch/powerpc/sysdev/xive/spapr.c | 34 ++++++-------------------------- 1 file changed, 6 insertions(+), 28 deletions(-) diff --git a/arch/powerpc/sysdev/xive/spapr.c b/arch/powerpc/sysdev/xive/spapr.c index e45419264391..2b3b8ad75b42 100644 --- a/arch/powerpc/sysdev/xive/spapr.c +++ b/arch/powerpc/sysdev/xive/spapr.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include #include @@ -41,7 +42,6 @@ struct xive_irq_bitmap { unsigned long *bitmap; unsigned int base; unsigned int count; - spinlock_t lock; struct list_head list; }; @@ -55,7 +55,6 @@ static int __init xive_irq_bitmap_add(int base, int count) if (!xibm) return -ENOMEM; - spin_lock_init(&xibm->lock); xibm->base = base; xibm->count = count; xibm->bitmap = bitmap_zalloc(xibm->count, GFP_KERNEL); @@ -81,47 +80,26 @@ static void xive_irq_bitmap_remove_all(void) } } -static int __xive_irq_bitmap_alloc(struct xive_irq_bitmap *xibm) -{ - int irq; - - irq = find_first_zero_bit(xibm->bitmap, xibm->count); - if (irq != xibm->count) { - set_bit(irq, xibm->bitmap); - irq += xibm->base; - } else { - irq = -ENOMEM; - } - - return irq; -} - static int xive_irq_bitmap_alloc(void) { struct xive_irq_bitmap *xibm; - unsigned long flags; - int irq = -ENOENT; list_for_each_entry(xibm, &xive_irq_bitmaps, list) { - spin_lock_irqsave(&xibm->lock, flags); - irq = __xive_irq_bitmap_alloc(xibm); - spin_unlock_irqrestore(&xibm->lock, flags); - if (irq >= 0) - break; + int irq = find_and_set_bit(xibm->bitmap, xibm->count); + + if (irq < xibm->count) + return irq + xibm->base; } - return irq; + return -ENOENT; } static void xive_irq_bitmap_free(int irq) { - unsigned long flags; struct xive_irq_bitmap *xibm; list_for_each_entry(xibm, &xive_irq_bitmaps, list) { if ((irq >= xibm->base) && (irq < xibm->base + xibm->count)) { - spin_lock_irqsave(&xibm->lock, flags); clear_bit(irq - xibm->base, xibm->bitmap); - spin_unlock_irqrestore(&xibm->lock, flags); break; } } -- 2.43.0