/* * Copyright (C) 2007 by Alan Stern * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2 of the License, or (at your * option) any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software Foundation, * Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ /* this file is part of ehci-hcd.c */ /* Display the ports dedicated to the companion controller */ static ssize_t show_companion(struct device *dev, struct device_attribute *attr, char *buf) { struct ehci_hcd *ehci; int nports, index, n; int count = PAGE_SIZE; char *ptr = buf; ehci = hcd_to_ehci(dev_get_drvdata(dev)); nports = HCS_N_PORTS(ehci->hcs_params); for (index = 0; index < nports; ++index) { if (test_bit(index, &ehci->companion_ports)) { n = scnprintf(ptr, count, "%d\n", index + 1); ptr += n; count -= n; } } return ptr - buf; } /* * Dedicate or undedicate a port to the companion controller. * Syntax is "[-]portnum", where a leading '-' sign means * return control of the port to the EHCI controller. */ static ssize_t store_companion(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct ehci_hcd *ehci; int portnum, new_owner; ehci = hcd_to_ehci(dev_get_drvdata(dev)); new_owner = PORT_OWNER; /* Owned by companion */ if (sscanf(buf, "%d", &portnum) != 1) return -EINVAL; if (portnum < 0) { portnum = - portnum; new_owner = 0; /* Owned by EHCI */ } if (portnum <= 0 || portnum > HCS_N_PORTS(ehci->hcs_params)) return -ENOENT; portnum--; if (new_owner) set_bit(portnum, &ehci->companion_ports); else clear_bit(portnum, &ehci->companion_ports); set_owner(ehci, portnum, new_owner); return count; } static DEVICE_ATTR(companion, 0644, show_companion, store_companion); /* * Display / Set uframe_periodic_max */ static ssize_t show_uframe_periodic_max(struct device *dev, struct device_attribute *attr, char *buf) { struct ehci_hcd *ehci; int n; ehci = hcd_to_ehci(dev_get_drvdata(dev)); n = scnprintf(buf, PAGE_SIZE, "%d\n", ehci->uframe_periodic_max); return n; } static ssize_t store_uframe_periodic_max(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct ehci_hcd *ehci; unsigned uframe_periodic_max; unsigned uframe; unsigned long flags; ssize_t ret; ehci = hcd_to_ehci(dev_get_drvdata(dev)); if (kstrtouint(buf, 0, &uframe_periodic_max) < 0) return -EINVAL; if (uframe_periodic_max < 100 || uframe_periodic_max >= 125) { ehci_info(ehci, "rejecting invalid request for " "uframe_periodic_max=%u\n", uframe_periodic_max); return -EINVAL; } ret = -EINVAL; /* * lock, so that our checking does not race with possible periodic * bandwidth allocation through submitting new urbs. */ spin_lock_irqsave (&ehci->lock, flags); /* * for request to decrease max periodic bandwidth, we have to check * to see whether the decrease is possible. */ if (uframe_periodic_max < ehci->uframe_periodic_max) { u8 allocated_max = 0; for (uframe = 0; uframe < EHCI_BANDWIDTH_SIZE; ++uframe) allocated_max = max(allocated_max, ehci->bandwidth[uframe]); if (allocated_max > uframe_periodic_max) { ehci_info(ehci, "cannot decrease uframe_periodic_max because " "periodic bandwidth is already allocated " "(%u > %u)\n", allocated_max, uframe_periodic_max); goto out_unlock; } } /* increasing is always ok */ ehci_info(ehci, "setting max periodic bandwidth to %u%% " "(== %u usec/uframe)\n", 100*uframe_periodic_max/125, uframe_periodic_max); if (uframe_periodic_max != 100) ehci_warn(ehci, "max periodic bandwidth set is non-standard\n"); ehci->uframe_periodic_max = uframe_periodic_max; ret = count; out_unlock: spin_unlock_irqrestore (&ehci->lock, flags); return ret; } static DEVICE_ATTR(uframe_periodic_max, 0644, show_uframe_periodic_max, store_uframe_periodic_max); static inline int create_sysfs_files(struct ehci_hcd *ehci) { struct device *controller = ehci_to_hcd(ehci)->self.controller; int i = 0; /* with integrated TT there is no companion! */ if (!ehci_is_TDI(ehci)) i = device_create_file(controller, &dev_attr_companion); if (i) goto out; i = device_create_file(controller, &dev_attr_uframe_periodic_max); out: return i; } static inline void remove_sysfs_files(struct ehci_hcd *ehci) { struct device *controller = ehci_to_hcd(ehci)->self.controller; /* with integrated TT there is no companion! */ if (!ehci_is_TDI(ehci)) device_remove_file(controller, &dev_attr_companion); device_remove_file(controller, &dev_attr_uframe_periodic_max); } m>2017-01-25 15:35:11 +0530 commit91539eb1fda2d530d3b268eef542c5414e54bf1a (patch) tree960f5ca6342ad20837aff18aad6e8ecd7da32fd6 /tools/scripts/utilities.mak parent6610d0edf6dc7ee97e46ab3a538a565c79d26199 (diff)
dmaengine: pl330: fix double lock
The static bug finder EBA (http://www.iagoabal.eu/eba/) reported the following double-lock bug: Double lock: 1. spin_lock_irqsave(pch->lock, flags) at pl330_free_chan_resources:2236; 2. call to function `pl330_release_channel' immediately after; 3. call to function `dma_pl330_rqcb' in line 1753; 4. spin_lock_irqsave(pch->lock, flags) at dma_pl330_rqcb:1505. I have fixed it as suggested by Marek Szyprowski. First, I have replaced `pch->lock' with `pl330->lock' in functions `pl330_alloc_chan_resources' and `pl330_free_chan_resources'. This avoids the double-lock by acquiring a different lock than `dma_pl330_rqcb'. NOTE that, as a result, `pl330_free_chan_resources' executes `list_splice_tail_init' on `pch->work_list' under lock `pl330->lock', whereas in the rest of the code `pch->work_list' is protected by `pch->lock'. I don't know if this may cause race conditions. Similarly `pch->cyclic' is written by `pl330_alloc_chan_resources' under `pl330->lock' but read by `pl330_tx_submit' under `pch->lock'. Second, I have removed locking from `pl330_request_channel' and `pl330_release_channel' functions. Function `pl330_request_channel' is only called from `pl330_alloc_chan_resources', so the lock is already held. Function `pl330_release_channel' is called from `pl330_free_chan_resources', which already holds the lock, and from `pl330_del'. Function `pl330_del' is called in an error path of `pl330_probe' and at the end of `pl330_remove', but I assume that there cannot be concurrent accesses to the protected data at those points. Signed-off-by: Iago Abal <mail@iagoabal.eu> Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'tools/scripts/utilities.mak')