netfs: zero the tail of a short DIO/unbuffered readgrafted

The buffered read collector zero-fills the tail of a short read that
stops below the inode's i_size (netfs_clear_unread()), so a read that
races an extending write still returns the expected number of bytes.
The non-buffered collector path does no such thing: it just records
how much was transferred.

Add the same zero-fill for the non-buffered case, gated on
NETFS_SREQ_CLEAR_TAIL: a subreq's source sets that flag when a short
result from it is known to be safe to treat as a hole, as opposed to
NETFS_SREQ_HIT_EOF, which means the read genuinely ran off the end of
the file and should be reported short as-is. Only CLEAR_TAIL should
zero-fill here; a real EOF must stay a real short read.

No source currently sets CLEAR_TAIL on an unbuffered/DIO subrequest,
so this is inert on its own -- a following change teaches cifs to set
it in the one case that needs it.

Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item")
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org

1 files changed, 201 insertions, 0 deletions

diff --git a/drivers/bcma/driver_pcie2.c b/drivers/bcma/driver_pcie2.c
new file mode 100644
index 000000000..cf889fc62
--- /dev/null
+++ b/drivers/bcma/driver_pcie2.c
@@ -0,0 +1,201 @@
+/*
+ * Broadcom specific AMBA
+ * PCIe Gen 2 Core
+ *
+ * Copyright 2014, Broadcom Corporation
+ * Copyright 2014, Rafał Miłecki <zajec5@gmail.com>
+ *
+ * Licensed under the GNU/GPL. See COPYING for details.
+ */
+
+#include "bcma_private.h"
+#include <linux/bcma/bcma.h>
+#include <linux/pci.h>
+
+/**************************************************
+ * R/W ops.
+ **************************************************/
+
+#if 0
+static u32 bcma_core_pcie2_cfg_read(struct bcma_drv_pcie2 *pcie2, u32 addr)
+{
+	pcie2_write32(pcie2, BCMA_CORE_PCIE2_CONFIGINDADDR, addr);
+	pcie2_read32(pcie2, BCMA_CORE_PCIE2_CONFIGINDADDR);
+	return pcie2_read32(pcie2, BCMA_CORE_PCIE2_CONFIGINDDATA);
+}
+#endif
+
+static void bcma_core_pcie2_cfg_write(struct bcma_drv_pcie2 *pcie2, u32 addr,
+				      u32 val)
+{
+	pcie2_write32(pcie2, BCMA_CORE_PCIE2_CONFIGINDADDR, addr);
+	pcie2_write32(pcie2, BCMA_CORE_PCIE2_CONFIGINDDATA, val);
+}
+
+/**************************************************
+ * Init.
+ **************************************************/
+
+static u32 bcma_core_pcie2_war_delay_perst_enab(struct bcma_drv_pcie2 *pcie2,
+						bool enable)
+{
+	u32 val;
+
+	/* restore back to default */
+	val = pcie2_read32(pcie2, BCMA_CORE_PCIE2_CLK_CONTROL);
+	val |= PCIE2_CLKC_DLYPERST;
+	val &= ~PCIE2_CLKC_DISSPROMLD;
+	if (enable) {
+		val &= ~PCIE2_CLKC_DLYPERST;
+		val |= PCIE2_CLKC_DISSPROMLD;
+	}
+	pcie2_write32(pcie2, (BCMA_CORE_PCIE2_CLK_CONTROL), val);
+	/* flush */
+	return pcie2_read32(pcie2, BCMA_CORE_PCIE2_CLK_CONTROL);
+}
+
+static void bcma_core_pcie2_set_ltr_vals(struct bcma_drv_pcie2 *pcie2)
+{
+	/* LTR0 */
+	pcie2_write32(pcie2, BCMA_CORE_PCIE2_CONFIGINDADDR, 0x844);
+	pcie2_write32(pcie2, BCMA_CORE_PCIE2_CONFIGINDDATA, 0x883c883c);
+	/* LTR1 */
+	pcie2_write32(pcie2, BCMA_CORE_PCIE2_CONFIGINDADDR, 0x848);
+	pcie2_write32(pcie2, BCMA_CORE_PCIE2_CONFIGINDDATA, 0x88648864);
+	/* LTR2 */
+	pcie2_write32(pcie2, BCMA_CORE_PCIE2_CONFIGINDADDR, 0x84C);
+	pcie2_write32(pcie2, BCMA_CORE_PCIE2_CONFIGINDDATA, 0x90039003);
+}
+
+static void bcma_core_pcie2_hw_ltr_war(struct bcma_drv_pcie2 *pcie2)
+{
+	u8 core_rev = pcie2->core->id.rev;
+	u32 devstsctr2;
+
+	if (core_rev < 2 || core_rev == 10 || core_rev > 13)
+		return;
+
+	pcie2_write32(pcie2, BCMA_CORE_PCIE2_CONFIGINDADDR,
+		      PCIE2_CAP_DEVSTSCTRL2_OFFSET);
+	devstsctr2 = pcie2_read32(pcie2, BCMA_CORE_PCIE2_CONFIGINDDATA);
+	if (devstsctr2 & PCIE2_CAP_DEVSTSCTRL2_LTRENAB) {
+		/* force the right LTR values */
+		bcma_core_pcie2_set_ltr_vals(pcie2);
+
+		/* TODO:
+		 *si_core_wrapperreg(pcie2, 3, 0x60, 0x8080, 0);
+		 */
+
+		/* enable the LTR */
+		devstsctr2 |= PCIE2_CAP_DEVSTSCTRL2_LTRENAB;
+		pcie2_write32(pcie2, BCMA_CORE_PCIE2_CONFIGINDADDR,
+			      PCIE2_CAP_DEVSTSCTRL2_OFFSET);
+		pcie2_write32(pcie2, BCMA_CORE_PCIE2_CONFIGINDDATA, devstsctr2);
+
+		/* set the LTR state to be active */
+		pcie2_write32(pcie2, BCMA_CORE_PCIE2_LTR_STATE,
+			      PCIE2_LTR_ACTIVE);
+		usleep_range(1000, 2000);
+
+		/* set the LTR state to be sleep */
+		pcie2_write32(pcie2, BCMA_CORE_PCIE2_LTR_STATE,
+			      PCIE2_LTR_SLEEP);
+		usleep_range(1000, 2000);
+	}
+}
+
+static void pciedev_crwlpciegen2(struct bcma_drv_pcie2 *pcie2)
+{
+	u8 core_rev = pcie2->core->id.rev;
+	bool pciewar160, pciewar162;
+
+	pciewar160 = core_rev == 7 || core_rev == 9 || core_rev == 11;
+	pciewar162 = core_rev == 5 || core_rev == 7 || core_rev == 8 ||
+		     core_rev == 9 || core_rev == 11;
+
+	if (!pciewar160 && !pciewar162)
+		return;
+
+/* TODO */
+#if 0
+	pcie2_set32(pcie2, BCMA_CORE_PCIE2_CLK_CONTROL,
+		    PCIE_DISABLE_L1CLK_GATING);
+#if 0
+	pcie2_write32(pcie2, BCMA_CORE_PCIE2_CONFIGINDADDR,
+		      PCIEGEN2_COE_PVT_TL_CTRL_0);
+	pcie2_mask32(pcie2, BCMA_CORE_PCIE2_CONFIGINDDATA,
+		     ~(1 << COE_PVT_TL_CTRL_0_PM_DIS_L1_REENTRY_BIT));
+#endif
+#endif
+}
+
+static void pciedev_crwlpciegen2_180(struct bcma_drv_pcie2 *pcie2)
+{
+	pcie2_write32(pcie2, BCMA_CORE_PCIE2_CONFIGINDADDR, PCIE2_PMCR_REFUP);
+	pcie2_set32(pcie2, BCMA_CORE_PCIE2_CONFIGINDDATA, 0x1f);
+}
+
+static void pciedev_crwlpciegen2_182(struct bcma_drv_pcie2 *pcie2)
+{
+	pcie2_write32(pcie2, BCMA_CORE_PCIE2_CONFIGINDADDR, PCIE2_SBMBX);
+	pcie2_write32(pcie2, BCMA_CORE_PCIE2_CONFIGINDDATA, 1 << 0);
+}
+
+static void pciedev_reg_pm_clk_period(struct bcma_drv_pcie2 *pcie2)
+{
+	struct bcma_drv_cc *drv_cc = &pcie2->core->bus->drv_cc;
+	u8 core_rev = pcie2->core->id.rev;
+	u32 alp_khz, pm_value;
+
+	if (core_rev <= 13) {
+		alp_khz = bcma_pmu_get_alp_clock(drv_cc) / 1000;
+		pm_value = (1000000 * 2) / alp_khz;
+		pcie2_write32(pcie2, BCMA_CORE_PCIE2_CONFIGINDADDR,
+			      PCIE2_PVT_REG_PM_CLK_PERIOD);
+		pcie2_write32(pcie2, BCMA_CORE_PCIE2_CONFIGINDDATA, pm_value);
+	}
+}
+
+void bcma_core_pcie2_init(struct bcma_drv_pcie2 *pcie2)
+{
+	struct bcma_bus *bus = pcie2->core->bus;
+	struct bcma_chipinfo *ci = &bus->chipinfo;
+	u32 tmp;
+
+	tmp = pcie2_read32(pcie2, BCMA_CORE_PCIE2_SPROM(54));
+	if ((tmp & 0xe) >> 1 == 2)
+		bcma_core_pcie2_cfg_write(pcie2, 0x4e0, 0x17);
+
+	switch (bus->chipinfo.id) {
+	case BCMA_CHIP_ID_BCM4360:
+	case BCMA_CHIP_ID_BCM4352:
+		pcie2->reqsize = 1024;
+		break;
+	default:
+		pcie2->reqsize = 128;
+		break;
+	}
+
+	if (ci->id == BCMA_CHIP_ID_BCM4360 && ci->rev > 3)
+		bcma_core_pcie2_war_delay_perst_enab(pcie2, true);
+	bcma_core_pcie2_hw_ltr_war(pcie2);
+	pciedev_crwlpciegen2(pcie2);
+	pciedev_reg_pm_clk_period(pcie2);
+	pciedev_crwlpciegen2_180(pcie2);
+	pciedev_crwlpciegen2_182(pcie2);
+}
+
+/**************************************************
+ * Runtime ops.
+ **************************************************/
+
+void bcma_core_pcie2_up(struct bcma_drv_pcie2 *pcie2)
+{
+	struct bcma_bus *bus = pcie2->core->bus;
+	struct pci_dev *dev = bus->host_pci;
+	int err;
+
+	err = pcie_set_readrq(dev, pcie2->reqsize);
+	if (err)
+		bcma_err(bus, "Error setting PCI_EXP_DEVCTL_READRQ: %d\n", err);
+}